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Abstract:

One state detector detects an abnormal state or a normal state relating
to charge and discharge of a battery cell group in one battery module,
and generates one detection signal representing the detected state.
Another state detector detects an abnormal state or a normal state
relating to charge and discharge of another battery cell group in another
battery module, and generates another detection signal representing the
detected state. One operation processing device sends the one detection
signal generated by the one state detector to an external object. Another
operation processing device sends the other detection signal generated by
the other state detector to the external object. The one detection signal
generated by the one state detector is transmitted to at least one of the
other operation processing device and the other state detector via a
signal line.

Claims:

1. A battery system comprising: a first battery module; a second battery
module; and a first communication path, wherein said first battery module
includes a first battery cell group including one or a plurality of
battery cells, a first state detector that detects an abnormal state or a
normal state relating to charge and discharge of said first battery cell
group, and generates a first detection signal representing the detected
state, and a first communication circuit that sends the first detection
signal generated by said first state detector to an external object, said
second battery module includes a second battery cell group including one
or a plurality of battery cells, a second state detector that detects an
abnormal state or a normal state relating to charge and discharge of said
second battery cell group, and generates a second detection signal
representing the detected state, and a second communication circuit that
sends the second detection signal generated by said second state detector
to the external object, and said first communication path is provided to
transmit said first detection signal generated by said first state
detector to at least one of said second communication circuit and said
second state detector.

2. The battery system according to claim 1, wherein said first
communication path transmits the first detection signal generated by said
first state detector to at least one of said second communication circuit
and said second state detector via said first communication circuit.

3. The battery system according to claim 1, wherein said first
communication path includes a second communication path that transmits
the first detection signal generated by said first state detector to said
first communication circuit, and a third communication path that
transmits the first detection signal generated by said first state
detector to said second state detector.

4. The battery system according to claim 1, further comprising a fourth
communication path that transmits said second detection signal generated
by said second state detector to at least one of said first communication
circuit and said first state detector.

5. The battery system according to claim 4, wherein said fourth
communication path transmits said second detection signal generated by
said second state detector to at least one of said first communication
circuit and said first state detector via said second communication
circuit.

6. The battery system according to claim 4, wherein said fourth
communication path includes a fifth communication path that transmits the
second detection signal generated by said second state detector to said
second communication circuit, and a sixth communication path that
transmits the second detection signal generated by said second state
detector to said first state detector.

7. The battery system according to claim 1, further comprising a seventh
communication path that transmits the second detection signal generated
by said second state detector to the external object without passing
through said first and second communication circuits.

8. The battery system according to claim 1, comprising N (N is a natural
number of one or more) third battery modules which are 1st to N-th third
battery modules, an eighth communication path, and N ninth communication
paths which are 1st to N-th ninth communication paths, wherein each of
said N third battery modules includes a third battery cell group
including one or a plurality of battery cells, a third state detector
that detects an abnormal state or a normal state relating to charge and
discharge of said third battery cell group, and generates a third
detection signal representing the detected state, and a third
communication circuit that sends the third detection signal generated by
said third state detector to the external object, said eighth
communication path is provided to transmit said second detection signal
generated by said second state detector in said second battery module to
at least one of said third communication circuit and said third state
detector in the 1st third battery module, when N is one, the 1st ninth
communication path is provided to transmit said third detection signal
generated by said third state detector in said 1st third battery module
to at least one of said first communication circuit and said first state
detector in said first battery module, when N is 2 or more, the i-th (i
is a natural number of 1 to (N-1)) ninth communication path is provided
to transmit said third detection signal generated by said third state
detector in the i-th third battery module to at least one of said third
communication circuit and said third state detector in the (i+1)-th third
battery module, and the N-th ninth communication path is provided to
transmit said third detection signal generated by said third state
detector in the N-th third battery module to at least one of said first
communication circuit and said first state detector in said first battery
module.

9. An electric vehicle comprising: the battery system according to claim
1; a motor that is driven with electric power of said battery system; and
a driving wheel that rotates with a torque generated by said motor.

10. A movable body comprising: the battery system according to claim 1; a
main body; and a power source that converts the electric power from said
battery system into power for moving said main body.

11. A power storage device comprising: the battery system according to
claim 1; and a system controller that performs control relating to
discharge or charge of said first and second battery modules in said
battery system.

12. A power supply device connectable to an external object, comprising:
the power storage device according to claim 11; and an electric power
conversion device that is controlled by said system controller in said
power storage device, and converts electric power between said battery
system in said power storage device and said external object.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a battery system, and an electric
vehicle, a movable body, a power storage device, and a power supply
device including the same.

BACKGROUND ART

[0002] In battery systems used as driving sources for movable bodies such
as electric automobiles or electric storage devices, a plurality of
battery modules, which can be charged and discharged, are provided. Each
of the battery modules has a configuration in which a plurality of
batteries (battery cells) are connected in series, for example. The
battery systems are provided with detection devices that detect
abnormalities such as overcharge or overdischarge of the battery cells.

[0003] In an in-vehicle assembled battery control device discussed in
Patent Document 1, a plurality of simplified cell
overcharge/overdischarge detection devices are provided to correspond to
a plurality of cell groups constituting an assembled battery. Each of the
simplified cell overcharge/overdischarge detection devices determines
whether a battery cell in the corresponding cell group is overcharged or
overdischarged, and sends its result to a battery controller.

[0004][Patent Document 1] JP 2003-79059 A

SUMMARY OF INVENTION

[0005] In the in-vehicle assembled battery control device discussed in
Patent Document 1, the battery controller detects the overcharge or
overdischarge of the battery cell in the cell group. If a defect has
occurred in a communication path including a CPU (Central Processing
Unit) or an IC (Integrated Circuit) between the simplified cell
overcharge/overdischarge detection device and the battery controller,
however, a determination result of the overcharge or overdischarge of the
battery cell cannot be sent to the battery controller. In this case, the
overcharge or overdischarge of the battery cell cannot be stopped. This
results in decreased reliability of the simplified cell
overcharge/overdischarge detection device.

[0006] An object of the present invention is to provide a battery system
the reliability of which can be improved while an increase in cost is
suppressed, and an electric vehicle, a movable body, a power storage
device, and a power supply device including the same.

[0007] A battery system according to the present invention includes a
first battery module, a second battery module, and a first communication
path, in which the first battery module includes a first battery cell
group including one or a plurality of battery cells, a first state
detector that detects an abnormal state or a normal state relating to
charge and discharge of the first battery cell group, and generates a
first detection signal representing the detected state, and a first
communication circuit that sends the first detection signal generated by
the first state detector to an external object, the second battery module
includes a second battery cell group including one or a plurality of
battery cells, a second state detector that detects an abnormal state or
a normal state relating to charge and discharge of the second battery
cell group, and generates a second detection signal representing the
detected state, and a second communication circuit that sends the second
detection signal generated by the second state detector to the external
object, and the first communication path is provided to transmit the
first detection signal generated by the first state detector to at least
one of the second communication circuit and the second state detector.

[0008] According to the present invention, the reliabilities of a battery
system, and an electric vehicle, a movable body, a power storage device,
and a power supply device including the same are improved while an
increase in cost is suppressed.

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a block diagram illustrating a configuration of a battery
system according to a first embodiment.

[0010] FIG. 2 is a block diagram illustrating a configuration of a voltage
detector, a state detector, and a cell-voltage-balancing circuit in a
battery module.

[0013] FIG. 5 is a block diagram illustrating a configuration in which
each battery module includes a plurality of voltage detectors and a
plurality of state detectors.

[0014] FIG. 6 is a block diagram illustrating a configuration of a battery
system according to a second embodiment.

[0015] FIG. 7 is a block diagram illustrating a configuration of a battery
system according to a third embodiment.

[0016] FIG. 8 is a block diagram illustrating a configuration of a battery
system according to a fourth embodiment.

[0017] FIG. 9 is an external perspective view illustrating an example of a
battery module.

[0018] FIG. 10 is a block diagram illustrating a configuration of an
electric automobile including a battery system.

[0019] FIG. 11 is a block diagram illustrating a configuration of a power
supply device.

[0020] FIG. 12 is a block diagram illustrating a configuration of a
battery system according to a first modified example.

[0021] FIG. 13 is a block diagram illustrating a configuration of a
battery system according to a second modified example.

[0022] FIG. 14 is a block diagram illustrating a configuration of a
battery system in another example of the second modified example.

[0023] FIG. 15 is a block diagram illustrating a configuration of a
battery system according to a third modified example.

[0024] FIG. 16 is a block diagram illustrating a configuration of a
battery system in another example of the third modified example.

[0025] FIG. 17 is a block diagram illustrating a configuration of a
battery system according to a fourth modified example.

DESCRIPTION OF EMBODIMENTS

[1] First Embodiment

[0026] A battery system according to a first embodiment will be described
with reference to the drawings. The battery system according to the
present embodiment is loaded in an electric vehicle (e.g. an electric
automobile) using electric power as a driving source. The battery system
can also be used for an electric storage device or consumer equipment
including a plurality of battery cells that can be charged and
discharged.

(1) Configuration of Battery System

[0027] FIG. 1 is a block diagram illustrating a configuration of the
battery system according to the first embodiment. As illustrated in FIG.
1, a battery system 500 includes a plurality of battery modules 100, a
battery ECU (Electronic Control Unit) 510, a contactor 520, an HV (High
Voltage) connector 530, and a service plug 540. In the present
embodiment, the battery system 500 includes two battery modules 100. In
the following description, the two battery modules 100 are respectively
referred to as battery modules 100a and 100b.

[0028] Each of the battery modules 100a and 100b includes a battery cell
group BL including a plurality of battery cells 10, a voltage detector
20, a state detector 30, an operation processing device 40, a
communication driver 60, and a cell-voltage-balancing circuit 70. The
plurality of battery cells 10 in the battery cell group BL are connected
in series. The battery cell groups BL are arranged adjacent to each other
while being integrally held as a battery block. A plurality of
thermistors TH (see FIG. 9, described below) for detecting a temperature
is attached to the battery cell group BL. Each of the battery cells 10 is
a secondary battery such as a lithium-ion battery or a nickel hydride
battery.

[0029] The respective battery cell groups BL in the plurality of battery
modules 100a and 100b are connected in series via a power supply line and
the service plug 540. The service plug 540 includes a switch for
electrically connecting or disconnecting the battery modules 100a and
100b. The switch in the service plug 540 is turned on so that all the
battery cells 10 in the plurality of battery modules 100a and 100b are
connected in series. At the time of maintenance of the battery system
500, for example, the switch in the service plug 540 is turned off. In
this case, no current flows in the battery modules 100a and 100b. This
can prevent a user from getting an electric shock even if he/she contacts
the battery modules 100a and 100b.

[0030] First, an operation of each unit in the battery module 100a will be
described. The voltage detector 20 detects a terminal voltage of each of
the plurality of battery cells 10, and feeds a detection signal DA
representing a value of the detected terminal voltage to the operation
processing device 40.

[0031] The state detector 30 detects the presence or absence of an
abnormality in the terminal voltage of each of the plurality of battery
cells 10 as an abnormality relating to charge and discharge of the
corresponding battery cell group BL, and generates a detection signal DT1
representing its detection result. The detection signal DT1 generated by
the state detector 30 in the battery module 100a is fed to the
corresponding operation processing device 40 via a connection line Q1
while being fed to the operation processing device 40 in the battery
module 100b via a signal line P1. In order to prevent each of the battery
cells 10 from being overdischarged and overcharged, an allowable voltage
range of the terminal voltage is defined. In the present embodiment, the
state detector 30 detects whether the terminal voltage of each of the
battery cells 10 is an upper limit of the allowable voltage range
(hereinafter referred to as an upper-limit voltage) or more while
detecting whether the terminal voltage is a lower limit of the allowable
voltage range (hereinafter referred to as a lower-limit voltage) or less.

[0032] The state detector 30 generates an "H"-level detection signal DT1,
for example, representing an abnormality if the terminal voltage of at
least one of the battery cells 10 in the corresponding battery cell group
BL is the upper-limit voltage or more or is the lower-limit voltage or
less (at the time of abnormality detection). The state detector 30
generates an "L"-level detection signal DT1, for example, representing a
normality if the terminal voltages of all the battery cells 10 in the
corresponding battery cell group BL are within the allowable voltage
range (at the time of normality detection).

[0033] The operation processing device 40 includes a CPU and a memory, or
a microcomputer, for example. The operation processing device 40 performs
CAN (Controller Area Network) communication, for example, via the
communication driver 60. Thus, the operation processing device 40 sends
the detection signal DT1 fed by the corresponding state detector 30 and a
detection signal DT2, described below, fed by the state detector 30 in
the battery module 100b to the battery ECU 510 via the communication
driver 60 and a bus BS. The operation processing device 40 sends a value
of the terminal voltage of each of the plurality of battery cells 10 to
the battery ECU 510 via the communication driver 60 and the bus BS based
on the detection signal DA fed from the voltage detector 20. Further, the
operation processing device 40 sends a value of a temperature of the
battery module 100a, which is given from the thermistors TH illustrated
in FIG. 9, described below, to the battery ECU 510 via the communication
driver 60 and the bus BS.

[0034] The operation processing device 40 performs various types of
arithmetic processing and determination processing using the value of the
terminal voltage of each of the plurality of battery cells 10 and the
value of the temperature. Further, the operation processing device 40
receives various types of command signals from the battery ECU 510 via
the bus BS and the communication driver 60.

[0035] Controlled by the operation processing device 40, the
cell-voltage-balancing circuit 70 performs equalization processing for
equalizing the terminal voltage of each of the plurality of battery cells
10 in the battery cell group BL.

[0036] A configuration and an operation of the battery module 100b are
similar to those of the battery module 100a except for the following
points.

[0037] The state detector 30 in the battery module 100b detects the
presence or absence of an abnormality in the terminal voltage of each of
the plurality of battery cells 10 as an abnormality relating to charge
and discharge of the corresponding battery cell group BL, and generates a
detection signal DT2 representing its detection result. The detection
signal DT2 generated by the state detector 30 in the battery module 100b
is fed to the corresponding operation processing device 40 via a
connection line Q2 while being fed to the operation processing device 40
in the battery module 100a via a signal line P2.

[0038] The state detector 30 generates an "H"-level detection signal DT2,
for example, representing an abnormality if the terminal voltage of at
least one of the battery cells 10 in the corresponding battery cell group
BL is the upper-limit voltage or more or is the lower-limit voltage or
less (at the time of abnormality detection). The state detector 30
generates an "L"-level detection signal DT2, for example, representing a
normality if the terminal voltages of all the battery cells 10 in the
corresponding battery cell group BL are within the allowable voltage
range (at the time of normality detection).

[0039] The operation processing device 40 in the battery module 100b sends
the detection signal DT2 fed by the corresponding state detector 30 and
the detection signal DT1 fed by the state detector 30 in the battery
module 100a to the battery ECU 510 via the communication driver 60 and
the bus BS. The operation processing device 40 sends a value of a
temperature of the battery module 100b, which is given from the
thermistors TH illustrated in FIG. 9, described below, to the battery ECU
510 via the communication driver 60 and the bus BS.

[0040] Based on the value of the terminal voltage of each of the plurality
of battery cells 10, which has been given from the operation processing
device 40 in each of the battery modules 100a and 100b, the battery ECU
510 calculates an SOC of the battery cell 10. Based on the value of the
terminal voltage of each of the plurality of battery cells 10, which has
been given from the operation processing device 40 in each of the battery
modules 100a and 100b, the battery ECU 510 determines the presence or
absence of an abnormality relating to charge and discharge of the battery
cell group BL in the battery module. The abnormality relating to charge
and discharge of the battery cell group BL in each of the battery modules
100a and 100b includes an abnormality in a current flowing in the battery
cell group BL, a terminal voltage of the battery cell 10, an SOC (State
of Charge), overdischarge, overcharge, or a temperature.

[0041] Further, based on the detection signals DT1 and DT2 respectively
fed from the operation processing devices 40 in the battery modules 100a
and 100b, the battery ECU 510 detects the presence or absence of an
abnormality in the terminal voltage of each of the plurality of battery
cells 10 in each of the battery modules 100a and 100b.

[0042] A power supply line connected to a positive electrode having the
highest potential of the battery module 100a and a power supply line
connected to a negative electrode having the lowest potential of the
battery module 100b are connected to the contactor 520. The contactor 520
is connected to a load (e.g. a motor) for an electric vehicle, for
example, via the HV connector 530. If an abnormality occurs in each of
the battery modules 100a and 100b, the battery ECU 510 turns off the
contactor 520. This prevents the battery modules 100a and 100b from
generating abnormal heat because no current flows through the plurality
of battery cells 10 when an abnormality occurs.

[0043] The battery ECU 510 is connected to a main controller 300 (see FIG.
10, described below) in an electric vehicle via a bus. An SOC of each of
the battery modules 100a and 100b (an SOC of the battery cell 10) is
given to the main controller 300 from the battery ECU 510. The main
controller 300 controls power of the electric vehicle (e.g., a rotational
speed of the motor) based on the SOC. When the SOC of each of the battery
modules 100a and 100b is reduced, the main controller 300 controls a
power generation device, which is not illustrated, connected to the power
supply line, to charge each of the battery modules 100a and 100b.

(2) Configuration of Voltage Detector and State Detector

[0044] FIG. 2 is a block diagram illustrating a configuration of the
voltage detector 20, the state detector 30, and the
cell-voltage-balancing circuit 70 in the battery module 100a.

[0045] The voltage detector 20 includes an ASIC (Application Specific
Integrated Circuit), for example. The voltage detector 20 includes a
plurality of differential amplifiers 21, a multiplexer 22, an ND
(Analog/Digital) converter 23, and a transmission circuit 24.

[0046] Each of the differential amplifiers 21 has two input terminals and
an output terminal. Each of the differential amplifiers 21 differentially
amplifies voltages respectively input to the two input terminals, and
outputs the amplified voltages from the output terminal. The two input
terminals of each of the differential amplifiers 21 are respectively
connected to a positive electrode and a negative electrode of the
corresponding battery cell 10 via conductor lines W1. Thus, the
differential amplifier 21 differentially amplifies a voltage between the
positive electrode and the negative electrode of the battery cell 10. An
output voltage of each of the differential amplifiers 21 corresponds to
the terminal voltage of the corresponding battery cell 10. The terminal
voltages output from the plurality of differential amplifiers 21 are fed
to the multiplexer 22. The multiplexer 22 sequentially outputs the
terminal voltages fed from the plurality of differential amplifiers 21 to
the A/D converter 23.

[0047] The A/D converter 23 converts the terminal voltage output from the
multiplexer 22 to a digital value. The digital value obtained by the A/D
converter 23 is given, as a detection signal DA representing a value of
the terminal voltage, to the operation processing device 40 (see FIG. 1)
via the transmission circuit 24.

[0048] The state detector 30 includes an ASIC, for example. The state
detector 30 includes a plurality of differential amplifiers 31, a
multiplexer 32, a switch circuit 33, reference voltage outputters 34 and
35, a comparator 36, a detection signal output circuit 37, a receiving
circuit 38a, and a transmission circuit 38b.

[0049] Each of the differential amplifiers 31 has two input terminals and
an output terminal. Each of the differential amplifiers 31 differentially
amplifies voltages respectively input to the two input terminals, and
outputs the amplified voltages from the output terminal. The two input
terminals of each of the differential amplifiers 31 are respectively
connected to a positive electrode and a negative electrode of the
corresponding battery cell 10 by conductor lines W1. Thus, the
differential amplifier 31 differentially amplifies a voltage between the
positive electrode and the negative electrode of the battery cell 10. An
output voltage of each of the differential amplifiers 31 corresponds to a
terminal voltage of the corresponding battery cell 10. The terminal
voltages output from the plurality of differential amplifiers 31 are fed
to the multiplexer 32. The multiplexer 32 sequentially outputs the
terminal voltages fed from the plurality of differential amplifiers 31 to
the comparator 36.

[0050] The switch circuit 33 has terminals CP0, CP1, and CP2. The
reference voltage outputter 34 outputs an upper-limit voltage Vth_O to
the terminal CP1 of the switch circuit 33. The reference voltage
outputter 35 outputs a lower-limit voltage Vth_U to the output terminal
CP2. The upper-limit voltage Vth_O is set to 4.2 V (not less than 4.19 V
and not more than 4.21 V), for example, and the lower-limit voltage Vth_U
is set to approximately 2.0 V (not less than 1.99 V and not more than
2.01 V), for example.

[0051] The comparator 36 has two input terminals and an output terminal.
One of the two input terminals of the comparator 36 is connected to the
multiplexer 32. The other input terminal of the comparator 36 is
connected to the terminal CP0 of the switch circuit 33. The switch
circuit 33 is switched so that the terminal CP0 is alternately connected
to the plurality of terminals CP1 and CP2 at a predetermined period.
Thus, the terminal voltage output from the multiplexer 32 is fed to the
one input terminal of the comparator 36 while the upper-limit voltage
Vth_O and the lower-limit voltage Vth_U are alternately fed to the other
input terminal of the comparator 36. In this case, the comparator 36
compares the terminal voltage of the battery cell 10, which is fed from
the multiplexer 32, with the upper-limit voltage Vth_O and the
lower-limit voltage Vth_U in this order, and outputs a signal
representing a comparison result to the detection signal output circuit
37.

[0052] The detection signal output circuit 37 determines whether the
terminal voltage of at least one of the plurality of battery cells 10 is
the upper-limit voltage Vth_O or more while determining whether the
terminal voltage of at least one of the plurality of battery cells 10 is
the lower-limit voltage Vth_U or less based on the signal output from the
comparator 36.

[0053] If the terminal voltage of at least one of the plurality of battery
cells 10 is the upper-limit voltage Vth_O or more or the lower-limit
voltage Vth_U or less, the detection signal output circuit 37 determines
that the terminal voltage in the corresponding battery cell group BL is
abnormal. If the terminal voltages of all the battery cells 10 are less
than the upper-limit voltage Vth_O and are more than the lower-limit
voltage Vth_U, the detection signal output circuit 37 determines that the
terminal voltage in the corresponding battery cell group BL is normal.

[0054] In an example illustrated in FIG. 1 and FIG. 6, described below, no
detection signal is fed to the receiving circuit 38a. Therefore, the
receiving circuit 38a need not be provided. The detection signal output
circuit 37 generates an "H"-level detection signal DT1, for example,
representing an abnormality if it determines that the terminal voltage in
the corresponding battery cell group BL is abnormal. The detection signal
output circuit 37 generates an "L"-level detection signal DT1, for
example, representing a normality if it determines that the terminal
voltage in the corresponding battery cell group BL is normal. The
transmission circuit 38b feeds the detection signal DT1 generated by the
detection signal output circuit 37 to the corresponding operation
processing device 40 via the connection line Q1 illustrated in FIG. 1
while feeding the detection signal DT1 to the operation processing device
40 in the battery module 100b via the signal line P1 illustrated in FIG.
1.

[0055] The cell-voltage-balancing circuit 70 includes a plurality of sets
of series circuits each including a resistor R and a switching element
SW. The one set of series circuits including the resistor R and the
switching element SW is connected between the positive electrode and the
negative electrode of each of the battery cells 10. The battery ECU 510
controls ON and OFF of the switching element SW via the operation
processing device 40 illustrated in FIG. 1. In a normal state, the
switching element SW is turned off.

[0056] A configuration of the voltage detector 20, the state detector 30,
and the cell-voltage-balancing circuit 70 in the battery module 100b
illustrated in FIG. 1 is similar to the configuration of the voltage
detector 20, the state detector 30, and the cell-voltage-balancing
circuit 70 in the battery module 100a except for the following points.

[0057] The detection signal output circuit 37 in the battery module 100b
generates an "H"-level detection signal DT2, for example, representing an
abnormality if it determines that the terminal voltage in the
corresponding battery cell group BL is abnormal. The detection signal
output circuit 37 generates an "L"-level detection signal DT2, for
example, representing a normality if it determines that the terminal
voltage in the corresponding battery cell group BL is normal. The
transmission circuit 38b in the battery module 100b feeds the detection
signal DT2 generated by the detection signal output circuit 37 to the
corresponding operation processing device 40 via the connection line Q2
illustrated in FIG. 1 while feeding the detection signal DT2 to the
operation processing device 40 in the battery module 100a via the signal
line P2.

(3) Configuration Example of Printed Circuit Board

[0058] The voltage detector 20, the state detector 30, the operation
processing device 40, the communication driver 60, and the
cell-voltage-balancing circuit 70 in each of the battery modules 100a and
100b illustrated in FIG. 1 are mounted on a rigid printed circuit board
(hereinafter referred to as a printed circuit board). FIG. 3 is a
schematic plan view illustrating a configuration example of the printed
circuit board. As illustrated in FIG. 3, insulating elements DIa, DIb,
and DIc and connectors CNa, CNb, CNc, and CNd are further mounted on the
printed circuit board 110. The printed circuit board 110 includes a first
mounting region MT1, a second mounting region MT2, and a strip-shaped
insulating region INS.

[0059] The second mounting region MT2 is formed at one corner of the
printed circuit board 110. The insulating region INS is formed to extend
along the second mounting region MT2. The first mounting region MT1 is
formed in the remaining portion of the printed circuit board 110. The
insulating region INS separates the first mounting region MT1 and the
second mounting region MT2 from each other. Thus, the insulating region
INS electrically insulates the first mounting region MT1 and the second
mounting region MT2 from each other.

[0060] The voltage detector 20, the state detector 30, and the
cell-voltage-balancing circuit 70 are mounted on the first mounting
region MT1. As a power supply of the voltage detector 20, the state
detector 30, and the cell-voltage-balancing circuit 70, a plurality of
battery cells 10 in the battery cell group BL are connected to the
voltage detector 20, the state detector 30, and the
cell-voltage-balancing circuit 70.

[0061] A ground pattern GND1 is formed in the first mounting region MT1
except for mounting regions of the voltage detector 20, the state
detector 30, and the cell-voltage-balancing circuit 70 and a formation
region of a connection line. The ground pattern GND1 is retained at a
reference potential (ground potential) of the plurality of battery cells
10 in the battery cell group BL.

[0062] The operation processing device 40, the communication driver 60,
and the connectors CNa to CNd are mounted on the second mounting region
MT2. As a power supply of the operation processing device 40 and the
communication driver 60, a non-driving battery BAT for an electric
vehicle is connected to the operation processing device 40 and the
communication driver 60.

[0063] A ground pattern GND2 is formed in the second mounting region MT2
except for mounting regions of the operation processing device 40, the
communication driver 60, and the connectors CNa to CNd and formation
regions of a plurality of connection lines. The ground pattern GND2 is
retained at the reference potential (ground potential) of the non-driving
battery BAT.

[0064] Thus, the plurality of battery cells 10 in the battery cell group
BL supply power to the voltage detector 20, the state detector 30, and
the cell-voltage-balancing circuit 70, and the non-driving battery BAT
supplies power to the operation processing device 40 and the
communication driver 60. Therefore, the operation processing device 40
and the communication driver 60 can be stably operated independently of
the voltage detector 20, the state detector 30, and the
cell-voltage-balancing circuit 70.

[0065] The insulating element DIa is mounted to cross the insulating
region INS. The insulating element DIa transmits a signal between the
voltage detector 20 and the operation processing device 40 while
electrically insulating the voltage detector 20 and the operation
processing device 40 from each other. The insulating element DIb is
mounted to cross the insulating region INS. The insulating element DIb
transmits a signal between the transmission circuit 38b (see FIG. 2) in
the state detector 30 and the operation processing device 40 via the
connection line Q1 (or the connection line Q2) while electrically
insulating the state detector 30 and the operation processing device 40
from each other. The insulating element DIb transmits a signal between
the transmission circuit 38b (see FIG. 2) in the state detector 30 and
the connector CNc while electrically insulating the state detector 30 and
the connector CNc from each other. The insulating element DIc is mounted
to cross the insulating region INS. The insulating element DIc transmits
a signal between the receiving circuit 38a (see FIG. 2) in the state
detector 30 and the connector CNd while electrically insulating the state
detector 30 and the connector CNd from each other. Examples of the
insulating elements DIa to DIc include a digital isolator and a photo
coupler. In the present embodiment, a digital isolator is used as the
insulating elements DIa to DIc.

[0066] In the second mounting region MT2, the operation processing device
40 and the connector CNa are connected to each other via the
communication driver 60. Thus, the value of the terminal voltage of each
of the plurality of battery cells 10 in each of the battery modules 100a
and 100b and the value of the temperature of the battery modules 100a and
100b, which are output from the operation processing device 40, are given
to the connector CNa via the communication driver 60. The bus BS
illustrated in FIG. 1 is connected to the connector CNa. The connector
CNb is connected to the operation processing device 40. The connector CNc
of the battery module 100a and the connector CNb of the battery module
100b are connected to each other via the signal line P1 illustrated in
FIG. 1. The connector CNb of the battery module 100a and the connector
CNc of the battery module 100b are connected to each other via the signal
line P2 illustrated in FIG. 1. In the example illustrated in FIG. 1 and
FIG. 6, described below, the insulating element DIc and the connector CNd
need not be provided.

(4) Another Configuration Example of Printed Circuit Board

[0067] Another configuration example of the printed circuit board 110 will
be described by referring to differences from the printed circuit board
110 illustrated in FIG. 3. FIG. 4 is a schematic plan view illustrating
another configuration example of a printed circuit board 110. As
illustrated in FIG. 4, an operation processing device 40 is mounted on
not a second mounting region MT2 but a first mounting region MT1.

[0068] A plurality of battery cells 10 in a battery cell group BL supply
power to the operation processing device 40. In this case, a
configuration for supplying power to a voltage detector 20, a state
detector 30, the operation processing device 40, and an
cell-voltage-balancing circuit 70 is simplified.

[0069] In the first mounting region MT2, the state detector 30 and the
operation processing device 40 are connected to each other via a
connection line Q1 (or a connection line Q2). A connector CNa is
connected to the operation processing device 40 via a communication
driver 60 and an insulating element DIa. A connector CNb is connected to
the operation processing device 40 via an insulating element DIb. A
connector CNc is connected to a transmission circuit 38b (see FIG. 2) in
the state detector 30 via the insulating element DIb. A connector CNd is
connected to a receiving circuit 38a (see FIG. 2) in the state detector
30 via an insulating element DIc. In the example illustrated in FIG. 1
and FIG. 6, described below, the insulating element DIc and the connector
CNd need not be provided.

(5) Equalization Processing of Terminal Voltage of Battery Cell

[0070] The battery ECU 510 acquires the value of the terminal voltage of
each of the battery cells 10, which has been detected by the voltage
detector 20, via the operation processing device 40. The battery ECU 510
feeds, if it determines that the value of the terminal voltage of any one
of the battery cells 10 is higher than that of the terminal voltage of
the other battery cell 10, a command signal for turning on the switching
element SW in the cell-voltage-balancing circuit 70 corresponding to the
battery cell 10 to the operation processing device 40. Thus, electric
charge charged in the battery cell 10 is discharged via the resistor R.

[0071] The battery ECU 510 feeds, if it determines that the value of the
terminal voltage of the battery cell 10 has decreased until it becomes
substantially equal to the value of the terminal voltage of the other
battery cell 10, a command signal for turning off the switching element
SW in the cell-voltage-balancing circuit 70 corresponding to the battery
cell 10 to the operation processing device 40. Thus, the values of the
terminal voltages of all the battery cells 10 are kept substantially
equal. This can prevent some of the battery cells 10 from being
overcharged or overdischarged. As a result, the battery cell 10 can be
prevented from being deteriorated.

(6) Another Example of Voltage Detector and State Detector

[0072] If the number of battery cells 10 in the battery cell group BL
included in each of the battery modules 100a and 100b is large or if a
withstand voltage of the voltage detector 20 or the state detector 30 is
low, the battery modules 100a and 100b may include a plurality of the
voltage detectors 20 and a plurality of state detectors 30 connected in
series.

[0073] FIG. 5 is a block diagram illustrating a configuration in which
each of the battery modules 100a and 100b includes a plurality of voltage
detectors 20 and a plurality of state detectors 30. FIG. 5 illustrates a
configuration of the battery module 100a. In an example illustrated in
FIG. 5, the battery module 100a includes three voltage detectors 20 and
three state detectors 30.

[0074] The one voltage detector 20 (hereinafter referred to as a voltage
detector for low-potential 20L) corresponds to battery cells 10 on the
low-potential side (hereinafter referred to as a battery cell group for
low-potential 10L), the number of which is one third of the total number
of the plurality of battery cells 10. The other voltage detector 20
(hereinafter referred to as a voltage detector for intermediate-potential
20M) corresponds to battery cells 10 at an intermediate potential
(hereinafter referred to as a battery cell group for
intermediate-potential 10M), the number of which is one third of the
total number of the plurality of battery cells 10. The still other
voltage detector 20 (hereinafter referred to as a voltage detector for
high-potential 20H) corresponds to battery cells 10 on the high-potential
side (hereinafter referred to as a battery cell group for high-potential
10H), the number of which is one third (six in this example) of the total
number of the plurality of battery cells 10.

[0075] The voltage detector for low-potential 20L detects a terminal
voltage of each of the plurality of battery cells 10 in the battery cell
group for low-potential 10L. The voltage detector for
intermediate-potential 20M detects a terminal voltage of each of the
plurality of battery cells 10 in the battery cell group for
intermediate-potential 10M. The voltage detector for high-potential 20H
detects a terminal voltage of each of the plurality of battery cells 10
in the battery cell group for high-potential 10H.

[0076] A detection signal DA output from a transmission circuit 24 (see
FIG. 2) in the voltage detector for high-potential 20H is fed to a
transmission circuit 24 (see FIG. 2) in the voltage detector for
low-potential 20L via a transmission circuit 24 (see FIG. 2) in the
voltage detector for intermediate-potential 20M, and is fed to an
operation processing device 40 from the transmission circuit 24 in the
voltage detector for low-potential 20L. A detection signal DA output from
the transmission circuit 24 in the voltage detector for
intermediate-potential 20M is fed to the transmission circuit 24 in the
voltage detector for low-potential 20L, and is fed to the operation
processing device 40 from the transmission circuit 24 in the voltage
detector for low-potential 20L. A detection signal DA output from the
transmission circuit 24 in the voltage detector for low-potential 20L is
fed to the operation processing device 40.

[0077] The one state detector 30 (hereinafter referred to as a state
detector for low-potential 30L) corresponds to the battery cell group for
low-potential 10L. The other state detector 30 (hereinafter referred to
as a state detector for intermediate-potential 30M) corresponds to the
battery cell group for intermediate-potential 10M. The still other state
detector 30 (hereinafter referred to as a state detector for
high-potential 30H) corresponds to the battery cell group for
high-potential 10H.

[0078] The state detector for low-potential 30L detects the presence or
absence of an abnormality in each of the plurality of battery cells 10 in
the battery cell group for low-potential 10L. The state detector for
intermediate-potential 30M detects the presence or absence of an
abnormality in each of the plurality of battery cells 10 in the battery
cell group for intermediate-potential 10M. The state detector for
high-potential 30H detects the presence or absence of an abnormality in
each of the plurality of battery cells 10 in the battery cell group for
high-potential 10H.

[0079] In this case, a transmission circuit 38b (see FIG. 2) in the state
detector for high-potential 30H and a receiving circuit 38a (see FIG. 2)
in the state detector for intermediate-potential 30M are connected to
each other. A transmission circuit 38b (see FIG. 2) in the state detector
for intermediate-potential 30M and a receiving circuit 38a (see FIG. 2)
in the state detector for low-potential 30L are connected to each other.
A transmission circuit 38b (see FIG. 2) in the state detector for
low-potential 30L is connected to the operation processing device 40 (see
FIGS. 3 and 4) via an insulating element DIb (see FIGS. 3 and 4) while
being connected to a connector CNc (see FIGS. 3 and 4) via the insulating
element DIb. A receiving circuit 38a in the state detector for
high-potential 30H need not be provided.

[0080] In the state detector for high-potential 30H, a detection signal
output circuit 37 (see FIG. 2) generates an "H"-level detection signal
DT1H, for example, representing an abnormality if it determines that the
terminal voltage in the corresponding battery cell group for
high-potential 10H is abnormal. The detection signal output circuit 37
generates an "L"-level detection signal DT1H, for example, representing a
normality if it determines that the terminal voltage in the corresponding
battery cell group for high-potential 10H is normal. The transmission
circuit 38b (see FIG. 2) feeds the detection signal DT1H generated by the
detection signal output circuit 37 to the state detector for
intermediate-potential 30M.

[0081] In the state detector for intermediate-potential 30M, the receiving
circuit 38a (see FIG. 2) feeds the detection signal DT1H fed by the state
detector for high-potential 30H to the detection signal output circuit 37
(see FIG. 2). The detection signal output circuit 37 generates an
"H"-level detection signal DT1M, for example, representing an abnormality
if it determines that the terminal voltage in the corresponding battery
cell group for intermediate-potential 10M is abnormal or if the detection
signal DT1 H fed by the receiving circuit 38a is at an "H" level
(abnormal). The detection signal output circuit 37 generates an "L"-level
detection signal DT1M, for example, representing a normality if it
determines that the terminal voltage in the corresponding battery cell
group for intermediate-potential 10M is normal and the detection signal
DT1 H fed by the receiving circuit 38a is at an "L" level (normal). The
transmission circuit 38b (see FIG. 2) feeds the detection signal DT1M
generated by the detection signal output circuit 37 to the state detector
for low-potential 30L.

[0082] In the state detector for low-potential 30L, the receiving circuit
38a (see FIG. 2) feeds the detection signal DT1M fed by the state
detector for intermediate-potential 30M to the detection signal output
circuit 37 (see FIG. 2). The detection signal output circuit 37 generates
an "H"-level detection signal DT1L, for example, representing an
abnormality if it determines that the terminal voltage in the
corresponding battery cell group for low-potential 10L is abnormal or if
the detection signal DT1M fed by the receiving circuit 38a is at an "H"
level (abnormal). The detection signal output circuit 37 generates an
"L"-level detection signal DT1L, for example, representing a normality if
it determines that the terminal voltage in the corresponding battery cell
group for low-potential 10L is normal and the detection signal DT1M fed
by the receiving circuit 38a is at an "L" level (normal). The
transmission circuit 38b (see FIG. 2) feeds the detection signal DT1L
generated by the detection signal output circuit 37, as a detection
signal DT1, to the corresponding operation processing device 40 (see FIG.
1) and a signal line P1 (see FIG. 1).

[0083] An operation of the state detector 30 in the other battery module
100b is similar to an operation of the state detector 30 in the battery
module 100a except for the following points. The state detector for
low-potential 30L in the battery module 100b feeds a detection signal
DT2, instead of the detection signal DT1, to the corresponding operation
processing device 40 (see FIG. 1) and a signal line P2 (see FIG. 1).

(7) Operation and Effects of Battery System

[0084] The battery cell group BL, the voltage detector 20, the state
detector 30, the operation processing device 40, and the communication
driver 60 in the battery module 100a are respectively referred to as a
battery cell group BLa, a voltage detector 20a, a state detector 30a, an
operation processing device 40a, and a communication driver 60a. The
battery cell group BL, the voltage detector 20, the state detector 30,
the operation processing device 40, and the communication driver 60 in
the battery module 100b are respectively referred to as a battery cell
group BLb, a voltage detector 20b, a state detector 30b, an operation
processing device 40b, and a communication driver 60b.

[0085] In the battery module 100a, the state detector 30a generates a
detection signal DT1 representing an abnormality if it determines that a
terminal voltage in the corresponding battery cell group

[0086] BLa is abnormal. On the other hand, the state detector 30a
generates a detection signal DT1 representing a normality if it
determines that a terminal voltage in the corresponding battery cell
group BLa is normal. The detection signal DT1 generated by the state
detector 30a is fed to the corresponding operation processing device 40a
via the connection line Q1 while being fed to the operation processing
device 40b in the battery module 100b via the signal line P1.

[0087] In the battery module 100b, the state detector 30b generates a
detection signal DT2 representing an abnormality if it determines that a
terminal voltage in the corresponding battery cell group BLb is abnormal.
On the other hand, the state detector 30b generates a detection signal
DT2 representing a normality if it determines that a terminal voltage in
the corresponding battery cell group BLb is normal. The detection signal
DT2 generated by the state detector 30b is fed to the corresponding
operation processing device 40b via the connection line Q2 while being
fed to the operation processing device 40a in the battery module 100a via
the signal line P2.

[0088] In the battery module 100a, the operation processing device 40a
feeds the detection signal DT1 fed by the corresponding state detector
30a and the detection signal DT2 fed by the state detector 30b in the
battery module 100b to the battery ECU 510 via the communication driver
60a and the bus BS.

[0089] In the battery module 100b, the operation processing device 40b
feeds the detection signal DT2 fed by the corresponding state detector
30b and the detection signal DT1 fed by the state detector 30a in the
battery module 100a to the battery ECU 510 via the communication driver
60b and the bus BS.

[0090] More specifically, in the present embodiment, the state detector
30a serving as a first state detector generates, when it detects an
abnormal state relating to charge and discharge of the battery cell group
BLa serving as a first battery cell group in the battery module 100a
serving as a first battery module, the detection signal DT1 serving as a
first detection signal. The state detector 30b serving as a second state
detector generates, when it detects an abnormal state relating to charge
and discharge of the battery cell group BL2 serving as a second battery
cell group in the battery module 100b serving as a second battery module,
the state detector DT2 serving as a second detection signal.

[0091] The operation processing device 40a serving as a first
communication circuit sends the detection signal DT1 generated by the
state detector 30a to an external object. More specifically, the
detection signal DT1 generated by the state detector 30a is transmitted
to the operation processing device 40a via the connection line Q1 serving
as a second communication path while being transmitted to the operation
processing device 40b via the signal line P1 serving as a first
communication path.

[0092] The operation processing device 40b serving as a second
communication circuit sends the detection signal DT2 generated by the
state detector 30b to an external object. More specifically, the
detection signal DT2 generated by the state detector 30b is transmitted
to the operation processing device 40b via the connection line Q2 serving
as a fifth communication path while being transmitted to the operation
processing device 40a via the signal line P2 serving as a fourth
communication path.

[0093] If the terminal voltages of all the battery cells 10 in the battery
modules 100a and 100b are thus determined to be normal, the battery ECU
510 acquires the detection signals DT1 and DT2 representing a normality
from the battery modules 100a and 100b, respectively. On the other hand,
if the terminal voltage of at least one of the battery cells 10 in the
battery modules 100a and 100b is determined to be abnormal, the battery
ECU 510 acquires the detection signals DT1 and DT2 representing an
abnormality from the battery modules 100a and 100b, respectively. Thus,
the battery ECU 510 can detect the presence or absence of an abnormality
in the terminal voltage of each of the plurality of battery cells 10 in
each of the battery modules 100a and 100b.

[0094] According to the above-mentioned configuration, even if the
operation processing device 40a or the communication driver 60a in the
battery module 100a has failed or if a defect has occurred in the
connection line Q1, the detection signal DT1 can be sent to the battery
ECU 510 from the state detector 30a in the battery module 100a via the
signal line P1, the operation processing device 40b and the communication
driver 60b in the battery module 100b, and the bus BS. Even if the
operation processing device 40b or the communication driver 60b in the
battery module 100b has failed or if a defect has occurred in the
connection line Q2, the detection signal DT2 can be sent to the battery
ECU 510 from the state detector 30b in the battery module 100b via the
signal line P2, the operation processing device 40a, and the
communication driver 60a in the battery module 100a, and the bus BS.
Therefore, the battery ECU 510 can be reliably notified of abnormalities
in the terminal voltages in the battery cell groups BLa and BLb without
providing an additional circuit in the battery system 500. This can
result in an improvement in the reliability of the battery system 500
while suppressing an increase in cost of the battery system 500.

[0095] Simultaneously, the battery ECU 510 acquires a value of the
terminal voltage of each of the plurality of battery cells 10 in the
battery cell group BLa from the voltage detector 20a in the battery
module 100a via the operation processing device 40a, the communication
driver 60a, and the bus BS. The battery ECU 510 acquires a value of the
terminal voltage of each of the plurality of battery cells 10 in the
battery cell group BLb from the voltage detector 20b in the battery
module 100b via the operation processing device 40b, the communication
driver 60b, and the bus BS. Thus, the battery ECU 510 can detect the
presence or absence of an abnormality in each of the plurality of battery
cells 10 in each of the battery modules 100a and 100b based on the
acquired values of the terminal voltages.

[0096] According to the above-mentioned configuration, even if the state
detector 30a and 30b have failed or if defects have occurred in the
signal lines P1 and P2, the battery ECU 510 can be notified of the value
of the terminal voltage in the battery cell group BLa, which has been
detected by the voltage detector 20a in the battery module 100a, via the
operation processing device 40a, the communication driver 60a, and the
bus BS. The battery ECU 510 can be notified of the value of the terminal
voltage in the battery cell group BLb, which has been detected by the
voltage detector 20b in the battery module 100b, via the operation
processing device 40b, the communication driver 60b, and the bus BS. On
the other hand, even if the voltage detectors 20a and 20b have failed,
the battery ECU 510 can be notified of an abnormality in the terminal
voltage in the battery cell group BLa, which has been detected by the
state detector 30a in the battery module 100a, via the connection line
Q1, the operation processing device 40a, the communication driver 60a,
and the bus BS. The battery ECU 510 can be notified of an abnormality in
the terminal voltage in the battery cell group BLb, which has been
detected by the state detector 30b in the battery module 100b, via the
connection line Q2, the operation processing device 40b, the
communication driver 60b, and the bus BS. This can result in an
improvement in the reliability of the battery system 500.

[2] Second Embodiment

(1) Configuration of Battery System

[0097] A battery system 500 according to a second embodiment will be
described by referring to differences from the battery system 500
according to the first embodiment. FIG. 6 is a block diagram illustrating
a configuration of the battery system 500 according to the second
embodiment.

[0098] As illustrated in FIG. 6, a state detector 30a in a battery module
100a detects the presence or absence of an abnormality in a terminal
voltage of each of a plurality of battery cells 10 in a corresponding
battery cell group BLa, and generates a detection signal DT1 representing
its detection result. The detection signal DT1 generated by the state
detector 30a in the battery module 100a is fed to a corresponding
operation processing device 40a via a connection line Q1 while being fed
to an operation processing device 40b in a battery module 100b via a
signal line P1.

[0099] A state detector 30b in the battery module 100b detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLb,
and generates a detection signal DT2 representing its detection result.
The detection signal DT2 generated by the state detector 30b in the
battery module 100b is fed to a corresponding operation processing device
40b via a connection line Q2 while being fed to a battery ECU 510 via a
signal line P2.

[0100] In this case, a connector CNc of a printed circuit board 110 (see
FIGS. 3 and 4) in the battery module 100a and a connector CNb of a
printed circuit board 110 (see FIGS. 3 and 4) in the battery module 100b
are connected to each other via the signal line P1. A connector CNc of
the printed circuit board 110 in the battery module 100b and the battery
ECU 510 are connected to each other via the signal line P2. A connector
CNb need not be provided in the printed circuit board 110 in the battery
module 110a.

(2) Operation and Effects of Battery System p In the battery module 100a,
the detection signal DT1 generated by the state detector 30a is fed to
the corresponding operation processing device 40a via the connection line
Q1 while being fed to the operation processing device 40b in the battery
module 100b via the signal line P1. In the battery module 100b, the
detection signal DT2 generated by the state detector 30b is fed to the
corresponding operation processing device 40b via the connection line Q2
while being fed to the battery ECU 510 via the signal line P2.

[0101] In the battery module 100a, the operation processing device 40a
feeds the detection signal DT1 fed by the corresponding state detector
30a to the battery ECU 510 via a communication driver 60a and a bus BS.
In the battery module 100b, the operation processing device 40b feeds the
detection signal DT2 fed by the corresponding state detector 30b and the
detection signal DT1 fed by the state detector 30a in the battery module
100a to the battery ECU 510 via a communication driver 60b and the bus
BS.

[0102] More specifically, the detection signal DT1 generated by the state
detector 30a is transmitted to the operation processing device 40a via
the connection line Q1 serving as a second communication path while being
transmitted to the operation processing device 40b via the signal line P1
serving as a first communication path. The detection signal DT2 generated
by the state detector 30b is transmitted to the operation processing
device 40b via the connection line Q2 serving as a fifth communication
path while being transmitted to the battery ECU 510 serving as an
external object via the signal line P2 serving as a seventh communication
path.

[0103] According to the above-mentioned configuration, even if the
operation processing device 40a or the communication driver 60a in the
battery module 100a has failed or if a defect has occurred in the
connection line Q1, the detection signal DT1 can be sent to the battery
ECU 510 from the state detector 30a in the battery module 100a via the
signal line P1, the operation processing device 40b and the communication
driver 60b in the battery module 100b, and the bus BS. Even if the
operation processing device 40b or the communication driver 60b in the
battery module 100b has failed or if a defect has occurred in the
connection line Q2, the detection signal DT2 can be sent to the battery
ECU 510 from the state detector 30b in the battery module 100b via the
signal line P2. Therefore, the battery ECU 510 can be reliably notified
of abnormalities in the terminal voltages in the battery cell groups BLa
and BLb without providing an additional communication circuit in the
battery system 500. This can result in an improvement in the reliability
of the battery system 500 while suppressing an increase in cost of the
battery system 500.

[3] Third Embodiment

(1) Configuration of Battery System

[0104] A battery system 500 according to a third embodiment will be
described by referring to differences from the battery system 500
according to the first embodiment. FIG. 7 is a block diagram illustrating
a configuration of the battery system 500 according to the third
embodiment.

[0105] As illustrated in FIG. 7, a state detector 30a in a battery module
100a detects the presence or absence of an abnormality in a terminal
voltage of each of a plurality of battery cells 10 in a corresponding
battery cell group BLa, and generates a detection signal DT1 representing
its detection result. The detection signal DT1 generated by the state
detector 30a in the battery module 100a is fed to a corresponding
operation processing device 40a via a connection line Q1 while being fed
to a state detector 30b in a battery module 100b via a signal line P1.

[0106] The state detector 30b in the battery module 100b detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLb,
and generates a detection signal DT2 based on its detection result and
the detection signal DT1 fed from the state detector 30a in the battery
module 100a. The detection signal DT2 generated by the state detector 30b
in the battery module 100b is fed to a corresponding operation processing
device 40b via a connection line Q2 while being fed to a battery ECU 510
via a signal line P2.

[0107] In this case, a connector CNc of a printed circuit board 110 (see
FIGS. 3 and 4) in the battery module 100a and a connector CNd of a
printed circuit board 110 (see FIGS. 3 and 4) in the battery module 100b
are connected to each other via the signal line P1. A connector CNc of
the printed circuit board 110 in the battery module 100b and the battery
ECU 510 are connected to each other via the signal line P2. Connectors
CNb and CNd and an insulating element DIc (see FIGS. 3 and 4) need not be
provided in the printed circuit board 110 in the battery module 110a.

(2) Operation and Effects of Battery System

[0108] In the battery module 100a, the detection signal DT1 generated by
the state detector 30a is fed to the corresponding operation processing
device 40a via the connection line Q1 while being fed to the state
detector 30b in the battery module 100b via the signal line P1.

[0109] A receiving circuit 38a (see FIG. 2) in the state detector 30b in
the battery module 100b feeds the detection signal DT1, which has been
fed to the connector CNd, to a detection signal output circuit 37. The
detection signal output circuit 37 generates an "H"-level detection
signal DT2, for example, representing an abnormality if it determines
that the terminal voltage in the corresponding battery cell group BL is
abnormal or if the detection signal DT1 fed by the receiving circuit 38a
is at an "H" level (abnormal). The detection signal output circuit 37
generates an "L"-level detection signal DT2, for example, representing a
normality if it determines that the terminal voltage in the corresponding
battery cell group BL is normal and the detection signal DT1 fed by the
receiving circuit 38a is at an "L" level (normal). A transmission circuit
38b outputs the detection signal DT2 generated by the detection signal
output circuit 37. Thus, in the battery module 100b, the detection signal
DT2 generated by the state detector 30b is fed to the corresponding
operation processing device 40b via the connection line Q2 while being
fed to the battery ECU 510 via the signal line P2. More specifically, if
the terminal voltage in the battery cell group BLa in the battery module
100a is abnormal, the detection signal DT1 representing an abnormality is
fed, as the detection signal DT2, to the operation processing device 40b
in the battery module 100b and the battery ECU 510 from the state
detector 30b in the battery module 100b.

[0110] In the battery module 100a, the operation processing device 40a
feeds the detection signal DT1, which has been fed by the corresponding
state detector 30a, to the battery ECU 510 via a communication driver 60a
and a bus BS. In the battery module 100b, the operation processing device
40b feeds the detection signal DT2 fed by the corresponding state
detector 30b to the battery ECU 510 via a communication driver 60b and
the bus BS.

[0111] More specifically, the detection signal DT1 generated by the state
detector 30a is transmitted to the operation processing device 40a via
the connection line Q1 serving as a second communication path while being
transmitted to the state detector 30b via the signal line P1 serving as a
third communication path. The detection signal DT2 generated by the state
detector 30b is transmitted to the operation processing device 40b via
the connection line Q2 serving as a fifth communication path while being
transmitted to the battery ECU 510 via the signal line P2 serving as a
seventh communication path.

[0112] According to the above-mentioned configuration, even if the
operation processing device 40a or the communication driver 60a in the
battery module 100a has failed or if a defect has occurred in the
connection line Q1, the detection signal DT1 can be sent, as the
detection signal DT2, to the battery ECU 510 from the state detector 30a
in the battery module 100a via the signal line P1, the state detector
30b, the operation processing device 40b, and the communication driver
60b in the battery module 100b, and the bus BS. The detection signal can
be sent, as the detection signal DT2, to the battery ECU 510 from the
state detector 30a in the battery module 100a via the signal line P1, and
the state detector 30b in the battery module 100b, and the signal line
P2.

[0113] Further, even if the operation processing device 40b or the
communication driver 60b in the battery module 100b has failed or if a
defect has occurred in the connection line Q2, the detection signal DT2
can be sent to the battery ECU 510 from the state detector 30b in the
battery module 100b via the signal line P2. Therefore, the battery ECU
510 can be notified of abnormalities in the terminal voltages in the
battery cell groups BLa and BLb without providing an additional
communication circuit in the battery system 500.

[0114] In the above-mentioned configuration, even if the operation
processing device 40a and the communication driver 60a in the battery
module 100a and the operation processing device 40b and the communication
driver 60b in the battery module 100b have failed and defects have
occurred in the connection lines Q1 and Q2, the battery ECU 510 can be
notified of abnormalities in the terminal voltages in the battery cell
groups BLa and BLb. This can further improve the reliability of the
battery system 500 while suppressing an increase in cost of the battery
system 500.

[4] Fourth Embodiment

(1) Configuration of Battery System

[0115] A battery system 500 according to a fourth embodiment will be
described by referring to differences from the battery system 500
according to the third embodiment. FIG. 8 is a block diagram illustrating
a configuration of the battery system 500 according to the fourth
embodiment.

[0116] As illustrated in FIG. 8, a state detector 30a in a battery module
100a detects the presence or absence of an abnormality in a terminal
voltage of each of a plurality of battery cells 10 in a corresponding
battery cell group BLa, and generates a detection signal DT1 representing
its detection result. The detection signal DT1 generated by the state
detector 30a in the battery module 100a is fed to a corresponding
operation processing device 40a via a connection line Q1 while being fed
to a state detector 30b in a battery module 100b via a signal line P1.
The detection signal DT1 generated by the state detector 30a in the
battery module 100a is fed to an operation processing device 40b in the
battery module 100b via a signal line P3.

[0117] The state detector 30b in the battery module 100b detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLb,
and generates a detection signal DT2 based on its detection result and
the detection signal DT1 fed form the state detector 30a in the battery
module 100a. The detection signal DT2 generated by the state detector 30b
in the battery module 100b is fed to a corresponding operation processing
device 40b via a connection line Q2 while being fed to a battery ECU 510
via a signal line P2.

[0118] In this case, a connector CNc of a printed circuit board 110 (see
FIGS. 3 and 4) in the battery module 100a and a connector CNd of a
printed circuit board 110 (see FIGS. 3 and 4) in the battery module 100b
are connected to each other via the signal line P1. The connector CNc of
the printed circuit board 110 in the battery module 100a and a connector
CNb of the printed circuit board 110 in the battery module 100b are
connected to each other via the signal line P3. Further, a connector CNc
of the printed circuit board 110 in the battery module 100b and the
battery ECU 510 are connected to each other via the signal line P2.
Connectors CNb and CNd and an insulating element DIc (see FIGS. 3 and 4)
need not be provided in the printed circuit board 110 in the battery
module 110a.

(2) Operation and Effects of Battery System

[0119] In the battery module 100a, the detection signal DT1 generated by
the state detector 30a is fed to the corresponding operation processing
device 40a via the connection line Q1 while being fed to the state
detector 30b in the battery module 100b via the signal line P1. The
detection signal DT1 generated by the state detector 30a is fed to the
operation processing device 40b in the battery module 100b via the signal
line P3. In the battery module 100b, the detection signal DT2 generated
by the state detector 30b is fed to the corresponding operation
processing device 40b via the signal line Q2 while being fed to the
battery ECU 510 via the signal line P2. More specifically, if the
terminal voltage in the battery cell group BLa in the battery module 100a
is abnormal, the detection signal representing an abnormality is fed, as
the detection signal DT2, to the operation processing device 40b in the
battery module 100b and the battery ECU 510 from the state detector 30b
in the battery module 100b.

[0120] In the battery module 100a, the operation processing device 40a
feeds the detection signal DT1, which has been fed by the corresponding
state detector 30a, to the battery ECU 510 via a communication driver 60a
and a bus BS. In the battery module 100b, the operation processing device
40b feeds the detection signal DT2 fed by the corresponding state
detector 30b and the detection signal DT1 fed by the state detector 30a
in the battery module 100a to the battery ECU 510 via a communication
driver 60b and the bus BS.

[0121] More specifically, the detection signal DT1 generated by the state
detector 30a is transmitted to the operation processing device 40a via
the connection line Q1 serving as a second communication path while being
transmitted to the operation processing device 40b via the signal line P1
serving as a first communication path and transmitted to the state
detector 30b via the signal line P3 serving as a third communication
path. The detection signal DT2 generated by the state detector 30b is
transmitted to the operation processing device 40b via the connection
line Q2 serving as a fifth communication path while being transmitted to
the battery ECU 510 via the signal line P2 serving as a seventh
communication path.

[0122] According to the above-mentioned configuration, even if the
operation processing device 40a or the communication driver 60a in the
battery module 100a has failed or if a defect has occurred in the
connection line Q1, the detection signal DT1 can be sent, as the
detection signal DT2, to the battery ECU 510 from the state detector 30a
in the battery module 100a via the signal line P1, the state detector
30b, the operation processing device 40b, and the communication driver
60b in the battery module 100b, and the bus BS. The detection signal DT1
can be sent, as the detection signal DT2, to the battery ECU 510 from the
state detector 30b in the battery module 100a via the signal line P1, the
state detector 30b in the battery module 100b, and the signal line P2.
Further, the detection signal DT1 can be sent to the battery ECU 510 from
the state detector 30a in the battery module 100a via the signal line P3,
the operation processing device 40b and the communication driver 60b in
the battery module 100b, and the bus BS.

[0123] Even if the operation processing device 40b or the communication
driver 60b in the battery module 100b has failed or if a defect has
occurred in the connection line Q2, the detection signal DT2 can be sent
to the battery ECU 510 from the state detector 30b in the battery module
100b via the signal line P2. Therefore, the battery ECU 510 can be
reliably notified of abnormalities in the terminal voltages in the
battery cell groups BLa and BLb without providing an additional
communication circuit in the battery system 500.

[0124] In the above-mentioned configuration, even if the operation
processing device 40a and the communication driver 60a in the battery
module 100a and the operation processing device 40b and the communication
driver 60b in the battery module 100b have failed and defects have
occurred in the connection lines Q1 and Q2, the battery ECU 510 can be
notified of abnormalities in the terminal voltages in the battery cell
groups BLa and BLb. This can further improve the reliability of the
battery system 500 while suppressing an increase in cost of the battery
system 500.

[5] Battery Module

[0125] A configuration of the battery module 100 will be described. FIG. 9
is an external perspective view illustrating an example of the battery
module 100. In FIG. 9, three directions that are perpendicular to one
another are respectively defined as an X-direction, a Y-direction, and a
Z-direction, as indicated by arrows X, Y, and Z. In this example, the
X-direction and the Y-direction are directions parallel to a horizontal
plane, and the Z-direction is a direction perpendicular to the horizontal
plane. An upward direction is a direction of the arrow Z.

[0126] As illustrated in FIG. 9, in the battery module 100, a plurality of
flat battery cells 10 having a substantially rectangular parallelepiped
shape are arranged to line up in the X-direction. A pair of end surface
frames EP having a substantially plate shape is arranged parallel to a
Y-Z plane. A pair of upper end frames FR1 and a pair of lower end frames
FE2 are arranged to extend in the X-direction. Connectors for connecting
the pair of upper end frames FR1 and the pair of lower end frames FR2 are
respectively formed at four corners of the pair of end surface frames EP.
While the plurality of battery cells 10 are arranged between the pair of
end surface frames EP, the pair of upper end frames FR1 is attached to
the connectors on the upper side of the pair of end surface frames EP,
and the pair of lower end frames FR2 is attached to the connectors on the
lower side of the pair of end surface frames EP. Thus, the pair of end
surface frames EP, the pair of upper end frames FR1, and the pair of
lower end frames FR2 integrally fix the plurality of battery cells 10.
The plurality of battery cells 10, the pair of end surface frames EP, the
pair of upper end frames FR1, and the pair of lower end frames FR2
constitute a battery block BLK having a substantially rectangular
parallelepiped shape. The battery block BLK includes a battery cell group
BL illustrated in FIG. 1.

[0127] A printed circuit board 110 is attached to the one end surface
frame EP. The plurality of thermistors TH, which detect the temperature
of the battery module 100, are attached to a side surface of the battery
block BLK.

[0128] Each of the battery cells 10 has a positive electrode 10a and a
negative electrode 10b on an upper surface of the battery block BLK to
line up in the Y-direction. In the battery module 100, the battery cells
10 are arranged so that a positional relationship between the positive
electrode 10a and the negative electrode 10b in the Y-direction of one of
the battery cells 10 is opposite to that of the adjacent battery cell 10.
The electrodes 10a and 10b at respective one ends in the Y-direction of
the plurality of battery cells 10 line up in the X-direction, and the
electrodes 10a and 10b at the respective other ends in the Y-direction of
the plurality of battery cells line up in the X-direction.

[0129] Thus, the positive electrode 10a of one of the two adjacent battery
cells 10 and the negative electrode 10b of the other battery cell 10 are
in close proximity to each other, and the negative electrode 10b of one
of the battery cells 10 and the positive electrode 10a of the other
battery cell 10 are in close proximity to each other. In this state, a
bus bar BB composed of copper, for example, is attached to the two
electrodes 10a and 10b in close proximity to each other. Thus, the
plurality of battery cells 10 are connected in series.

[0130] A long flexible printed circuit board (hereinafter abbreviated as
an FPC board) 120 extending in the X-direction 120 is common and
connected to a plurality of bus bars BB at the respective one ends in the
Y-direction of the plurality of battery cells 10. Similarly, a long FPC
board 120 extending in the X-direction is common and connected to the
plurality of bus bars BB at the respective other ends in the Y-direction
of the plurality of battery cells 10.

[0131] The FPC board 120 mainly has a configuration in which a plurality
of conductor lines W1 illustrated in FIG. 2, described below, are formed
on an insulating layer, and have bendability and flexibility. A material
for the insulating layer composing the FPC board 120 includes polyimide,
and a material for the conductor line W1 includes copper. Each of the FPC
boards 120 is folded at right angles inward and further folded downward
at an upper end portion of one of the end surface frames EP in the
battery cell group BL, and is connected to the printed circuit board 110.
Thus, the voltage detector 20, the state detector 30, and the
cell-voltage-balancing circuit 70 illustrated in FIG. 1 are connected to
the positive electrode 10a and the negative electrode 10b of the battery
cell 10.

[6] Electric Vehicle

(1) Configuration and Operation

[0132] An electric vehicle will be described. The electric vehicle
includes the battery system 500 according to the above-mentioned
embodiment. An electric automobile will be described below as an example
of the electric vehicle.

[0133] FIG. 10 is a block diagram illustrating a configuration of an
electric automobile including the battery system 500. As illustrated in
FIG. 10, an electric automobile 600 includes a vehicle body 610. The
vehicle body 610 includes the battery system 500 illustrated in FIG. 1,
and a non-driving battery BAT, an electric power converter 601, a motor
602, a driving wheel 603, an accelerator device 604, a brake device 605,
a rotational speed sensor 606, and a main controller 300. If the motor
602 is an alternating current (AC) motor, the electric power converter
601 includes an inverter circuit. The battery system 500 includes the
battery ECU 510 illustrated in FIG. 1.

[0134] The battery system 500 is connected to the motor 602 via the
electric power converter 601 while being connected to the main controller
300.

[0135] An SOC of the battery module 100 (see FIG. 1) is given to the main
controller 300 from the battery ECU 510 in the battery system 500. The
accelerator device 604, the brake device 605, and the rotational speed
sensor 606 are connected to the main controller 300. The main controller
300 includes a CPU and a memory, or a microcomputer, for example.

[0136] The accelerator device 604 includes an accelerator pedal 604a and
an accelerator detector 604b that detects an operation amount (depression
amount) of the accelerator pedal 604a, which are included in the electric
automobile 600. When a user operates the accelerator pedal 604a, the
accelerator detector 604b detects the operation amount of the accelerator
pedal 604a using a state where the accelerator pedal is not operated by
the user as a basis. The detected operation amount of the accelerator
pedal 604a is given to the main controller 300.

[0137] The brake device 605 includes a brake pedal 605a and a brake
detector 605b that detects an operation amount (depression amount) of the
brake pedal 605a by the user, which are included in the electric
automobile 600. When the user operates the brake pedal 605a, the brake
detector 605b detects the operation amount of the brake pedal 605a. The
detected operation amount of the brake pedal 605a is given to the main
controller 300. The rotational speed sensor 606 detects a rotational
speed of the motor 602. The detected rotational speed is given to the
main controller 300.

[0138] As described above, the SOC of the battery module 100, the
operation amount of the accelerator pedal 604a, the operation amount of
the brake pedal 605a, and the rotational speed of the motor 602 are given
to the main controller 300. The main controller 300 performs
charge/discharge control of the battery module 100 and electric power
conversion control of the electric power converter 601 based on the
information. When the electric automobile 600 is started and accelerated
based on an accelerator operation, for example, electric power of the
battery module 100 is supplied from the battery system 500 to the
electric power converter 601.

[0139] The main controller 300 calculates a torque (a command torque) to
be transmitted to the driving wheel 603 based on the given operation
amount of the accelerator pedal 604a, and feeds a control signal based on
the command torque to the electric power converter 601.

[0140] The electric power converter 601, which has received the
above-mentioned control signal, converts the electric power supplied from
the battery system 500 into electric power required to drive the driving
wheel 603 (driving electric power). Thus, the driving electric power
obtained in the conversion by the electric power converter 601 is
supplied to the motor 602, and a torque generated by the motor 602 based
on the driving electric power is transmitted to the driving wheel 603.

[0141] On the other hand, when the electric automobile 600 is decelerated
based on a braking operation, the motor 602 functions as a power
generation device. In this case, the electric power converter 601
converts regenerated electric power generated by the motor 602 into
electric power suited to charge the plurality of battery cells 10, and
feeds the electric power to the plurality of battery cells 10. Thus, the
plurality of battery cells 10 are charged.

(2) Effects

[0142] The motor 602 is driven with the electric power from the battery
system 500. The driving wheel 603 rotates with the torque generated by
the motor 602 so that the electric automobile 600 serving as the electric
vehicle moves.

[0143] In the electric automobile 600, the battery system 500 according to
the above-mentioned embodiment is provided. This can improve the
reliability of the electric automobile 600 while suppressing an increase
in cost of the electric automobile 600.

[0144] The main controller 300 may have a function of the battery ECU 510.
In this case, the main controller 300 is connected to the respective
communication drivers 60a and 60b (see FIG. 1) in the battery modules
100a and 100b included in each of the battery systems 500 via the bus BS.
In the second to fourth embodiments, the main controller 300 is further
connected to the state detector 30b (see FIG. 1) in the battery module
100b included in each of the battery systems 500 via the signal line P2.
If the main controller 300 has the function of the battery ECU 510, each
of the battery systems 500 need not be provided with the battery ECU 510.

(3) Another Movable Body

[0145] While an example in which the battery system 500 illustrated in
FIG. 1 is loaded in the electric vehicle has been described above, the
battery system 500 may be loaded in another movable body such as a ship,
an airplane, an elevator, or a walking robot.

[0146] The ship, which is loaded with the battery system 500, includes a
hull instead of the vehicle body 610 illustrated in FIG. 10, includes a
screw instead of the driving wheel 603, includes an acceleration inputter
instead of the accelerator device 604, and includes a deceleration
inputter instead of the brake device 605, for example. A driver operates
the acceleration inputter instead of the accelerator device 604 in
accelerating the hull, and operates the deceleration inputter instead of
the brake device 605 in decelerating the hull. In this case, the hull
corresponds to a main body, the motor corresponds to a power source, and
the screw corresponds to a driving unit. In such a configuration, the
motor receives electric power from the battery system 500, to convert the
electric power into power, and the screw is rotated with the power so
that the hull moves.

[0147] Similarly, the airplane, which is loaded with the battery system
500, includes an airframe instead of the vehicle body 610 illustrated in
FIG. 10, includes a propeller instead of the driving wheel 603, includes
an acceleration inputter instead of the accelerator device 604, and
includes a deceleration inputter instead of the brake device 605, for
example. In this case, the airframe corresponds to a main body, the motor
corresponds to a power source, and the propeller corresponds to a driving
unit. In such a configuration, the motor receives electric power from the
battery system 500, to convert the electric power into power, and the
propeller is rotated with the power so that the airframe moves.

[0148] The elevator, which is loaded with the battery system 500, includes
a cage instead of the vehicle body 610 illustrated in FIG. 10, includes
an hoist rope, which is attached to the cage, instead of the driving
wheel 603, includes an acceleration inputter instead of the accelerator
device 604, and includes a deceleration inputter instead of the brake
device 605, for example. In this case, the cage corresponds to a main
body, the motor corresponds to a power source, and the hoist rope
corresponds to a driving unit. In such a configuration, the motor
receives electric power from the battery system 500, to convert the
electric power into power, and the hoist rope is wound up with the power
so that the cage rises and falls.

[0149] The walking robot, which is loaded with the battery system 500,
includes a body instead of the vehicle body 610 illustrated in FIG. 10,
includes feet instead of the driving wheel 603, includes an acceleration
inputter instead of the accelerator device 604, and includes a
deceleration inputter instead of the brake device 605, for example. In
this case, the body corresponds to a movable body, the motor corresponds
to a power source, and the feet correspond to a driving unit. In such a
configuration, the motor receives electric power from the battery system
500, to convert the electric power into power, and the feet are driven
with the power so that the body moves.

[0150] Thus, the power source converts the electric power from the battery
system 500 into the power, and the main body moves with the power. In the
movable body, which is loaded with the battery system 500, the power
source receives the electric power from the battery system 500, to
convert the electric power into power, and the driving unit moves the
main body with the power obtained in the conversion by the power source.

[7] Power Supply Device

(1) Configuration and Operation

[0151] A power supply device will be described. FIG. 11 is a block diagram
illustrating a configuration of the power supply device. As illustrated
in FIG. 11, the power supply device 700 includes a power storage device
710 and an electric power conversion device 720. The power storage device
710 includes a battery system group 711 and a controller 712. The battery
system group 711 includes a plurality of battery systems 500. The
plurality of battery systems 500 may be connected to each other in
parallel, or may be connected to each other in series.

[0152] The controller 712 includes a CPU and a memory, or a microcomputer,
for example. The controller 712 is connected to the battery ECU 510 (see
FIG. 1) included in each of the battery systems 500. The controller 712
controls the electric power conversion device 720 based on an SOC of each
of battery cells 10, which has been given from the battery ECU 510. The
controller 712 performs control, described below, as control relating to
discharge or charge of the battery module 100 in the battery system 500.

[0153] The electric power conversion device 720 includes a DC/DC (direct
current/direct current) converter 721 and a DC/AC (direct
current/alternating current) inverter 722. The DC/DC converter 721 has
input/output terminals 721a and 721b, and the DC/AC inverter 722 has
input/output terminals 722a and 722b. The input/output terminal 721a of
the DC/DC converter 721 is connected to the battery system group 711 in
the power storage device 710 via an HV connector 530 (see FIG. 1) in each
of the battery systems 500.

[0154] The input/output terminal 721b of the DC/DC converter 721 and the
input/output terminal 722a of the DC/AC inverter 722 are connected to
each other while being connected to an electric power outputter PU1. The
input/output terminal 722b of the DC/AC inverter 722 is connected to an
electric power outputter PU2 while being connected to another electric
power system.

[0155] Each of the electric power outputters PU1 and PU2 has an outlet,
for example. Various loads, for example, are connected to the power
outputters PU1 and PU2. The other electric power system includes a
commercial power supply or a solar battery, for example. The power
outputters PU1 and PU2 and the other electric power system are examples
of external objects connected to the power supply device. If the solar
battery is used as the electric power system, the solar battery is
connected to the input/output terminal 721b of the DC/DC converter 721.
On the other hand, if a solar power generation system including the solar
battery is used as the electric power system, an AC outputter of a power
conditioner in the solar power generation system is connected to the
input/output terminal 722b of the DC/AC inverter 722.

[0156] The controller 712 controls the DC/DC converter 721 and the DC/AC
inverter 722 so that the battery system group 711 is discharged and
charged. When the battery system group 711 is discharged, the DC/DC
converter 721 performs DC/DC (direct current/direct current) conversion
of electric power fed from the battery system group 711, and the DC/AC
inverter 722 further performs DC/AC (direct current/alternating current)
conversion thereof.

[0157] If the power supply device 700 is used as a DC power supply,
electric power obtained in the DC/DC conversion by the DC/DC converter
721 is supplied to the power outputters PU1. If the power supply device
700 is used as an AC power supply, electric power obtained in the DC/AC
conversion by the DC/AC inverter 722 is supplied to the power outputter
PU2. AC electric power obtained in the conversion by the DC/AC converter
722 can also be supplied to another electric power system.

[0158] The controller 712 performs the following control as an example of
control relating to discharge of the battery module 100 in the battery
system group 711. When the battery system group 711 is discharged, the
controller 712 determines whether the discharge of the battery system
group 711 is stopped or whether a discharging current (or discharging
electric power) is restricted based on the calculated SOC, and controls
the electric power conversion device 720 based on a determination result.
More specifically, when an SOC of any one of the plurality of battery
cells 10 (see FIG. 1) included in the battery system group 711 becomes
smaller than a predetermined threshold value, the controller 712 controls
the DC/DC converter 721 and the DC/AC inverter 722 so that the discharge
of the battery system group 711 is stopped or the discharging current (or
the discharging electric power) is restricted. Thus, each of the battery
cells 10 is prevented from being overdischarged.

[0159] The discharging current (or the discharging electric power) is
restricted when a voltage of the battery system group 711 becomes a
predetermined reference voltage. The controller 712 sets the reference
voltage based on the SOC of the battery cell 10.

[0160] On the other hand, when the battery system group 711 is charged,
the DC/AC inverter 722 performs AC/DC (alternating current/direct
current) conversion of AC electric power fed from another electric power
system, and the DC/DC converter 721 further performs DC/DC (direct
current/direct current) conversion thereof. Electric power is fed from
the DC/DC converter 721 to the battery system group 711 so that the
plurality of battery cells 10 (see FIG. 1) included in the battery system
group 711 are charged.

[0161] The controller 712 performs the following control as an example of
control relating to charge of the battery module 100 in the battery
system group 711. When the battery system group 711 is charged, the
controller 712 determines whether the charge of the battery system group
711 is stopped or whether a charging current (or charging electric power)
is restricted based on the calculated SOC, and controls the electric
power conversion device 720 based on a determination result. More
specifically, when an SOC of any one of the plurality of battery cells 10
(see FIG. 1) included in the battery system group 711 becomes larger than
a predetermined threshold value, the controller 712 controls the DC/DC
converter 721 and the DC/AC inverter 722 so that the charge of the
battery system group 711 is stopped or the charging current (or the
charging electric power) is restricted. Thus, each of the battery cells
10 is prevented from being overcharged.

[0162] The charging current (or the charging electric power) is restricted
when a voltage of the battery system group 711 becomes a predetermined
reference voltage. The controller 712 sets the reference voltage based on
the SOC of the battery cell 10.

[0163] If electric power can be supplied between the power supply device
700 and the external object, the electric power conversion device 720 may
have only either one of the DC/DC converter 721 and the DC/AC inverter
722. If electric power can be supplied between the power supply device
700 and the external object, the electric power conversion device 720
need not be provided.

(2) Effects

[0164] In the power storage device 710, the controller 712 serving as a
system controller performs control relating to charge or discharge of the
battery modules 100a and 100b in the above-mentioned battery system 500.
Thus, the battery modules 100a and 100b can be prevented from being
deteriorated, overdischarged, and overcharged.

[0165] In the power supply device 700, the electric power conversion
device 720 performs electric power conversion between the battery system
500 and the external object. The electric power conversion device 720
performs control relating to charge or discharge of the battery modules
100a and 100b in the power storage device 710. More specifically, the
controller 712 controls supply of electric power between the battery
system group 711 and the external object. Thus, each of the battery cells
10 in the battery modules 100a and 100b included in the battery system
group 711 is prevented from being overdischarged and overcharged.

[0166] In the power supply device 700, the battery system 500 according to
the above-mentioned embodiment is provided. This can improve the
reliability of the power supply device 700 while suppressing an increase
in cost of the power supply device 700.

[0167] The controller 712 controls the electric power conversion device
720 if it detects an abnormality in a terminal voltage in the battery
cell group BL. Therefore, each of the battery systems 500 need not be
provided with the contactor 520 illustrated in FIG. 1.

[0168] The controller 712 may have a function of the battery ECU 510. In
this case, the controller 712 is connected to respective communication
drivers 60a and 60b (see FIG. 1) in the battery modules 100a and 100b
included in each of the battery systems 500 via the bus BS. In the second
to fourth embodiments, the controller 712 is further connected to the
state detector 30b (see FIG. 1) in the battery module 100b included in
each of the battery systems 500 via the signal line P3. If the controller
712 has the function of the battery ECU 510, each of the battery systems
500 need not be provided with the battery ECU 510.

[8] Other Embodiments

[0169] (1) While in the above-mentioned embodiments, the state detector 30
generates an "H"-level detection signal, for example, at the time of
abnormality detection, and generates an "L"-level detection signal, for
example, at the time of normality detection, the present invention is not
limited to this. The state detector 30 may generate a detection signal,
described below.

[0170] The state detector 30 generates a detection signal having a first
duty ratio (e.g., 75%) if a terminal voltage of at least one of battery
cells 10 in a corresponding battery cell group BL is an upper-limit
voltage or more (at the time of first abnormality detection). The state
detector 30 generates a detection signal having a second duty ratio
(e.g., 25%) when the terminal voltage of at least one of the battery
cells 10 in the corresponding battery cell group BL is a lower-limit
voltage or less (at the time of second abnormality detection). The state
detector 30 generates a detection signal having a third duty ratio (e.g.,
50%) at the time of normality detection.

[0171] If a short circuit to ground level occurs, the detection signal
reaches an "L" level. On the other hand, when a short circuit to power
supply line occurs, the detection signal reaches an "H" level. "Short
circuit to ground level" means a state where a signal line of a state
detector DT is disconnected while contacting a ground terminal or the
like so that the signal line is retained at a ground potential. "Short
circuit to power supply line" means a state where the signal line of the
state detector DT is disconnected while contacting a power supply
terminal or the like so that the signal line is retained at a power
supply potential. Therefore, a state detector 30, an operation processing
device 40, and a battery ECU 510 receive an "L"-level detection signal
when the short circuit to ground level occurs, and receive an "H"-level
detection signal when the short circuit to power supply line occurs.

[0172] The battery ECU 510 can detect the occurrences of the first and
second abnormalities, the normality, the short circuit to ground level,
and the short circuit to power supply line of the battery cells 10 by
receiving detection signals respectively having the above-mentioned first
to third duty ratios and the "L"-level detection signal and the "H"-level
detection signal.

[0173] (2) While the state detector 30 detects an abnormal state and a
normal state relating to charge and discharge of the battery cell group
BL, and generates a detection signal representing an abnormality or a
normality in the above-mentioned embodiments, the present invention is
not limited to this. The state detector 30 may detect only an abnormal
state relating to charge and discharge of the battery cell group BL, and
generate a detection signal representing only an abnormality. The state
detector 30 may detect only a normal state relating to charge and
discharge of the battery cell group BL, and generate a detection signal
representing only a normality.

[0174] (3) While the battery module 100 includes the plurality of battery
cells 10 in the above-mentioned embodiments, the present invention is not
limited to this. The battery module 100 may include one battery cell 10.

[0175] (4) While the detection signal DT1 generated by the state detector
30a in the battery module 100a is fed to at least one of the state
detector 30b and the operation processing device 40b in the battery
module 100b without passing through the operation processing device 40a
in the above-mentioned embodiments, the present invention is not limited
to this. The detection signal DT1 generated by the state detector 30a in
the battery module 100a may be fed to at least one of the state detector
30b and the operation processing device 40b in the battery module 100b by
passing through the operation processing device 40a.

[0176] Similarly, the detection signal DT2 generated by the state detector
30b in the battery module 100b may be fed to at least one of the state
detector 30a and the operation processing device 40a via the operation
processing device 40b.

[0177] FIG. 12 is a block diagram illustrating a configuration of a
battery system 500 according to a first modified example. As illustrated
in FIG. 12, a detection signal DT1 generated by a state detector 30a in a
battery module 100a is fed to a corresponding operation processing device
40a via a connection line Q1 while being fed to an operation processing
device 40b in a battery module 100b via the connection line Q1, the
operation processing device 40a, and a signal line P1.

[0178] A detection signal DT2 generated by a state detector 30b in the
battery module 100b is fed to the corresponding operation processing
device 40b via a connection line Q2 while being fed to the operation
processing device 40a in the battery module 100a via the connection line
Q2, the operation processing device 40b, and a signal line P2.

[0179] More specifically, the detection signal DT1 generated by the state
detector 30a is transmitted to the operation processing device 40a via
the connection line Q1 serving as a second communication path while being
transmitted to the operation processing device 40b via the connection
line Q1 and the signal line P1 serving as a first communication path. The
detection signal DT2 generated by the state detector 30b is transmitted
to the operation processing device 40b via the connection line Q2 serving
as a fifth communication path while being transmitted to the operation
processing device 40a via the connection line Q2 and the signal line P2
serving as a fourth communication path.

[0180] The detection signal DT1 generated by the state detector 30a in the
battery module 100a may be fed to the state detector 30b in the battery
module 100b via the connection line Q1, the operation processing device
40a, and the signal line P1. The detection signal DT1 generated by the
state detector 30a in the battery module 100a may be fed to the operation
processing device 40b in the battery module 100b via the connection line
Q1, the operation processing device 40a, and the signal line P1, and
further fed to the operation processing device 40b in the battery module
100b via the connection line Q1, the operation processing device 40a, and
another signal line.

[0181] The detection signal DT2 generated by the state detector 30b in the
battery module 100b may be fed to the state detector 30a in the battery
module 100a via the connection line Q2, the operation processing device
40b, and the signal line P2. The detection signal DT2 generated by the
state detector 30b in the battery module 100b may be fed to the operation
processing device 40a in the battery module 100a via the connection line
Q2, the operation processing device 40b, and the signal line P2, and
further fed to the operation processing device 40a in the battery module
100a via the connection line Q2, the operation processing device 40b, and
another signal line.

[0182] Each of the operation processing devices 40a and 40b includes a
plurality of communication terminals conforming to standards such as CAN,
UART (Universal Asynchronous Receiver Transmitter), I2C
(inter-Integrated Circuit), LIN (Local Interconnect Network), and
Ethernet (registered trademark). Therefore, the operation processing
devices 40a and 40b are easily connected to the plurality of
communication terminals.

[0183] Thus, the state detector 30a in the battery module 100a can easily
feed the detection signal DT1 to the state detector 30b and the operation
processing device 40b in the battery module 100b via a plurality of
communication terminals of the operation processing device 40a.
Similarly, the state detector 30b in the battery module 100b can easily
feed the detection signal DT2 to the state detector 30a and the operation
processing device 40a in the battery module 100a via a plurality of
communication terminals of the operation processing device 40b.

[0184] (5) While the battery system 500 includes the two battery modules
100a and 100b in the above-mentioned embodiments, the present invention
is not limited to this. The battery system 500 may include three or more
battery modules 100.

[0185] FIG. 13 is a block diagram illustrating a configuration of a
battery system 500 according to a second modified example. As illustrated
in FIG. 13, the battery system 500 further includes a battery module 100c
serving as a 1st third battery module in addition to a battery module
100a serving as a first battery module and a battery module 100b serving
as a second battery module. More specifically, the battery system 500
includes a first battery module, a second battery module, and N third
battery modules. N is one in the second modified example.

[0186] A configuration of the battery module 100c is similar to
configurations of the battery modules 100a and 100b. A battery cell group
BL, a voltage detector 20, a state detector 30, an operation processing
device 40, and a communication driver 60 in the battery module 100c are
respectively referred to as a battery cell group BLc, a voltage detector
20c, a state detector 30c, an operation processing device 40c, and a
communication driver 60c. In FIG. 13, illustration of the contactor 520,
the HV connector 530, and the service plug 540 illustrated in FIG. 1 is
omitted.

[0187] A state detector 30a in the battery module 100a detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLa,
and generates a detection signal DT1 representing its detection result.
The detection signal DT1 generated by the state detector 30a in the
battery module 100a is fed to a corresponding operation processing device
40a via a connection line Q1 while being fed to an operation processing
device 40b in the battery module 100b via a signal line P1.

[0188] A state detector 30b in the battery module 100b detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLb,
and generates a detection signal DT2 representing its detection result.
The detection signal DT2 generated by the state detector 30b in the
battery module 100b is fed to the corresponding operation processing
device 40b via a connection line Q2 while being fed to the operation
processing device 40c in the battery module 100c via a signal line P2.

[0189] The state detector 30c in the battery module 100c detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in the corresponding battery cell group
BLc, and generates a detection signal DT3 representing its detection
result. The detection signal DT3 generated by the state detector 30c in
the battery module 100c is fed to the corresponding operation processing
device 40a via a connection line Q3 while being fed to an operation
processing device 40a in the battery module 100a via a signal line P5.

[0190] More specifically, the state detector 30c serving as a third state
detector generates the detection signal DT3 serving as a third detection
signal when it detects an abnormal state relating to charge and discharge
of the battery cell group BLc serving as a third battery cell group in
the battery module 100c serving as a third battery module.

[0191] The detection signal DT1 generated by the state detector 30a is
transmitted to the operation processing device 40a via the connection
line Q1 serving as a second communication path while being transmitted to
the operation processing device 40b via a signal line P1 serving as a
first communication path. The detection signal DT2 generated by the state
detector 30b is transmitted to the operation processing device 40b via
the connection line Q2 serving as a fifth communication path while being
transmitted to the operation processing device 40c via the signal line P2
serving as an eighth communication path.

[0192] The detection signal DT3 generated by the state detector 30c in the
battery module 100c may be fed to a battery ECU 510 via the signal line
P5 without being fed to the operation processing device 40a in the
battery module 100a via the signal line P5.

[0193] In this case, a connector CNc of a printed circuit board 110 (see
FIGS. 3 and 4) in the battery module 100a and a connector CNb of a
printed circuit board 110 (see FIGS. 3 and 4) in the battery module 100b
are connected to each other via the signal line P1. A connector CNc of
the printed circuit board 110 in the battery module 100b and a connector
CNb of a printed circuit board 110 (see FIGS. 3 and 4) in the battery
module 100c are connected to each other via the signal line P2. Further,
a connector CNc of the printed circuit board 110 in the battery module
100c and a connector CNb of the printed circuit board 110 in the battery
module 100a are connected to each other via the signal line P5.

[0194] If the detection signal DT3 generated by the state detector 30c in
the battery module 100c is fed to the battery ECU 510 via the signal line
P5, the connector CNc of the printed circuit board 110 in the battery
module 100c and the battery ECU 510 are connected to each other via the
signal line P5. In this case, a connector CNb need not be provided in the
printed circuit board 110 in the battery module 100a.

[0195] In the second modified example, the detection signal DT1 generated
by the state detector 30a in the battery module 100a may be fed to at
least one of the state detector 30b and the operation processing device
40b in the battery module 100b via the operation processing device 40a.
The detection signal DT2 generated by the state detector 30b in the
battery module 100b may be fed to at least one of the state detector 30c
and the operation processing device 40c in the battery module 100c via
the operation processing device 40b. The detection signal DT3 generated
by the state detector 30c in the battery module 100c may be fed to at
least one of the state detector 30a and the operation processing device
40a in the battery module 100a via the operation processing device 40c.

[0196] FIG. 14 is a block diagram illustrating a configuration of a
battery system 500 according to another example of the second modified
example. In FIG. 14, illustration of the battery cell 10, the voltage
detector 20, the communication driver 60, and the cell-voltage-balancing
circuit 70 in each of battery modules 100a to 100c is omitted.
Illustration of the battery ECU 510, the contactor 520, the HV connector
530, and the service plug 540 illustrated in FIG. 1 is omitted.

[0197] A detection signal DT1 generated by a state detector 30a in a
battery module 100a is fed to an operation processing device 40b in a
battery module 100b via a signal line P1 while being further fed to an
operation processing device 40c in a battery module 100c via a signal
line P1'.

[0198] A detection signal DT2 generated by a state detector 30b in a
battery module 100b is fed to the operation processing device 40c in the
battery module 100c via a signal line P2 while being further fed to an
operation processing device 40a in the battery module 100a via a signal
line P2'.

[0199] A detection signal DT3 generated by a state detector 30c in the
battery module 100c is fed to the operation processing device 40a in the
battery module 100a via a signal line P5 while being further fed to the
operation processing device 40b in the battery module 100b via a signal
line P5'.

[0200] FIG. 15 is a block diagram illustrating a configuration of a
battery system 500 according to a third modified example. As illustrated
in FIG. 15, the battery system 500 includes a battery module 100a serving
as a first battery module, a battery module 100b serving as a second
battery module, a battery module 100c serving as a 1st third battery
module, and a battery module 100d serving as an N-th battery module. More
specifically, the battery system 500 includes a first battery module, a
second battery module, and N battery modules. N is two in the third
modified example.

[0201] A configuration of the battery module 100d is similar to
configurations of the battery modules 100a to 100c. A battery cell group
BL, a state detector 30, and an operation processing device 40 in the
battery module 100d are respectively referred to as a battery cell group
BLd, a state detector 30d, and an operation processing device 40d. In
FIG. 15, illustration of the battery cell 10, the voltage detector 20,
the communication driver 60, and the cell-voltage-balancing circuit 70 in
each of the battery modules 100a to 100d is omitted. Illustration of the
battery ECU 510, the contactor 520, the HV connector 530, and the service
plug 540 illustrated in FIG. 1 is omitted.

[0202] A state detector 30a in the battery module 100a detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLa,
and generates a detection signal DT1 representing its detection result.
The detection signal DT1 generated by the state detector 30a in the
battery module 100a is fed to a corresponding operation processing device
40a via a connection line Q1 while being fed to an operation processing
device 40b in the battery module 100b via a signal line P1 serving as a
first communication path. The detection signal DT1 generated by the state
detector 30a in the battery module 100a may be fed to a state detector
30b, as indicated by a one-dot and dash line, without being fed to the
operation processing device 40b in the battery module 100b.

[0203] The state detector 30b in the battery module 100b detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLb,
and generates a detection signal DT2 representing its detection result.
The detection signal DT2 generated by the state detector 30b in the
battery module 100b is fed to the corresponding operation processing
device 40b via a connection line Q2 while being fed to an operation
processing device 40c in the battery module 100c via a signal line P2
serving as an eighth communication path. The detection signal DT2
generated by the state detector 30b in the battery module 100b may be fed
to a state detector 30c, as indicated by a one-dot and dash line, without
being fed to the operation processing device 40c in the battery module
100c.

[0204] The state detector 30c in the battery module 100c detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in a corresponding battery cell group BLc,
and generates a detection signal DT3 representing its detection result.
The detection signal DT3 generated by the state detector 30c in the
battery module 100c is fed to the corresponding operation processing
device 40c via a connection line Q31 while being fed to the operation
processing device 40d in the battery module 100d via a signal line P51
serving as a 1st ninth communication path. The detection signal DT3
generated by the state detector 30c in the battery module 100c may be fed
to the state detector 30d, as indicated by a one-dot and dash line,
without being fed to the operation processing device 40d in the battery
module 100d.

[0205] The state detector 30d in the battery module 100d detects the
presence or absence of an abnormality in a terminal voltage of each of a
plurality of battery cells 10 in the corresponding battery cell group
BLd, and generates a detection signal DT4 representing its detection
result. The detection signal DT4 generated by the state detector 30d in
the battery module 100d is fed to the corresponding operation processing
device 40d via a connection line Q32 while being fed to the operation
processing device 40a in the battery module 100a via a signal line P52
serving as an N-th (2nd in this example) ninth communication path. The
detection signal DT4 generated by the state detector 30d in the battery
module 100d may be fed to the state detector 30a, as indicated by a
one-dot and dash line, without being fed to the operation processing
device 40a in the battery module 100a.

[0206] In the third modified example, the detection signal DT1 generated
by the state detector 30a in the battery module 100a may be fed to at
least one of the state detector 30b and the operation processing device
40b in the battery module 100b via the operation processing device 40a,
i.e., a first communication circuit. The detection signal DT2 generated
by the state detector 30b in the battery module 100b may be fed to at
least one of the state detector 30c and the operation processing device
40c in the battery module 100c via the operation processing device 40b,
i.e., a second communication circuit. The detection signal DT3 generated
by the state detector 30c in the battery module 100c may be fed to at
least one of the state detector 30d and the operation processing device
40d in the battery module 100d via the operation processing device 40c,
i.e., a 1st third communication circuit. The detection signal DT4
generated by the state detector 30d in the battery module 100d may be fed
to at least one of the state detector 30a and the operation processing
device 40a in the battery module 100a via the operation processing device
40d, i.e., a 2nd third communication circuit.

[0207] FIG. 16 is a block diagram illustrating a configuration of a
battery system 500 in another example of the third modified example. In
FIG. 16, illustration of the battery cell 10, the voltage detector 20,
the communication driver 60, and the cell-voltage-balancing circuit 70 in
each of battery modules 100a to 100d is omitted. Illustration of the
battery ECU 510, the contactor 520, the HV connector 530, and the service
plug 540 illustrated in FIG. 1 is omitted.

[0208] A detection signal DT1 generated by a state detector 30a in the
battery module 100a is fed to an operation processing device 40b in the
battery module 100b via a signal line P1 while being further fed to an
operation processing device 40d in the battery module 100d via a signal
line P1'. The detection signal DT1 generated by the state detector 30a in
the battery module 100a may be fed to a state detector 30d, as indicated
by a two-dot and dash line, without being fed to the operation processing
device 40d in the battery module 100d.

[0209] A detection signal DT2 generated by a state detector 30b in the
battery module 100b is fed to an operation processing device 40c in the
battery module 100c via a signal line P2 while being further fed to an
operation processing device 40a in the battery module 100a via a signal
line P2'. The detection signal DT2 generated by the state detector 30b in
the battery module 100b may be fed to the state detector 30a, as
indicated by a two-dot and dash line, without being fed to the operation
processing device 40a in the battery module 100a.

[0210] A detection signal DT3 generated by a state detector 30c in the
battery module 100c is fed to the operation processing device 40d in the
battery module 100d via a signal line P51 while being further fed to the
operation processing device 40b in the battery module 100b via a signal
line P51'. The detection signal DT3 generated by the state detector 30c
in the battery module 100c may be fed to the state detector 30b, as
indicated by a two-dot and dash line, without being fed to the operation
processing device 40b in the battery module 100b.

[0211] A detection signal DT4 generated by the state detector 30d in the
battery module 100d is fed to the operation processing device 40a in the
battery module 100a via a signal line P52 while being further fed to the
operation processing device 40c in the battery module 100c via a signal
line P52'. The detection signal DT4 generated by the state detector 30d
in the battery module 100d may be fed to the state detector 30c, as
indicated by a two-dot and dash line, without being fed to the operation
processing device 40c in the battery module 100c.

[0212] Each of the battery systems according to the second and third
modified examples further includes a tenth communication path (a signal
line P1') and N (N=1 in the example illustrated in FIG. 14, N=2 in the
example illustrated in FIG. 16) eleventh communication paths which are
1st to N-th eleventh communication paths (the signal lines P5' in the
example illustrated in FIG. 14, the signal lines P51' and P52' in the
example illustrated in FIG. 16). The tenth communication path is provided
to transmit a first detection signal (the detection signal DT1) generated
by a first state detector (the state detector 30a) in a first battery
module (the battery module 100a) to at least one of a third communication
circuit (the operation processing device 40c in the example illustrated
in FIG. 14, the operation processing device 40d in the example
illustrated in FIG. 16) in an N-th third battery module (the battery
module 100c in the example illustrated in FIG. 14, the battery module
100d in the example illustrated in FIG. 16) and a third state detector
(the state detector 30c illustrated in the example illustrated in FIG.
14, the state detector 30d in the example illustrated in FIG. 16). If N
is one (a case of the example illustrated in FIG. 14), a 1st eleventh
communication path (the signal line P5') is provided to transmit a third
detection signal (the detection signal DT3) generated by a third state
detector (the state detector 30c) in a 1st third battery module (the
battery module 100c) to at least one of a second communication circuit
(the operation processing device 40b) and a second state detector (the
state detector 30b) in a second battery module (the battery module 100b).
If N is two or more (a case of the example illustrated in FIG. 16), a
j-th (j is a natural number from 2 to N) eleventh communication path (the
signal line P52') is provided to transmit a third detection signal (the
detection signal DT4) generated by a third state detector (the state
detector 30d) in a j-th third battery module (the battery module 100d) to
at least one of a third communication circuit (the operation processing
device 40c) and a third state detector (the state detector 30c) in a
(j-1)-th third battery module (the battery module 100c). A 1st eleventh
communication path (the signal line P51') is provided to transmit a third
detection signal (the detection signal DT3) generated by the third state
detector (the state detector 30c) in the 1st third battery module (the
battery module 100c) to at least one of the second communication circuit
(the operation processing device 40b) and the second state detector (the
state detector 30b) in the second battery module (the battery module
100b).

[0213] In the battery systems according to the second and third modified
examples, the tenth communication path may transmit the first detection
signal via the first communication circuit. Similarly, the eleventh
communication path may transmit the third detection signal via the third
communication circuit.

[0214] (6) While the state detectors 30a and 30b detect abnormalities in
the terminal voltages of the plurality of battery cells 10 as
abnormalities relating to charge and discharge of the corresponding
battery cell groups BLa and BLb in the above-mentioned embodiments, the
present invention is not limited to this. The state detectors 30a and 30b
may detect abnormalities in currents flowing through the battery cell
groups BLa and BLb, an SOC (State of Charge) of the battery cell 10,
overdischarge, overcharge, or a temperature as abnormalities relating to
charge and discharge of the corresponding battery cell groups BLa and
BLb.

[0215] If the state detectors 30a and 30b detect the abnormalities in the
currents flowing through the battery cell groups BLa and BLb as
abnormalities relating to charge and discharge of the corresponding
battery cell groups BLa and BLb, the battery modules 100a and 100b
respectively have current detectors that detect the currents flowing
through the battery cell groups BLa and BLb.

[0216] (7) While the detection signal DT2 generated by the state detector
30b in the battery module 100b is fed to the operation processing device
40a in the battery module 100a in the first embodiment, the present
intention is not limited to this.

[0217] FIG. 17 is a block diagram illustrating a configuration of a
battery system 500 according to a fourth modified example. As illustrated
in FIG. 17, a detection signal DT2 generated by a state detector 30b in a
battery module 100b may be fed to a state detector 30a in a battery
module 100a via a signal line P4. In this case, a connector CNc (see
FIGS. 3 and 4) of the battery module 100b and a connector CNd (see FIGS.
3 and 4) of the battery module 100a are connected to each other via the
signal line P4. According to this configuration, the detection signal DT2
is fed, as a detection signal DT1, to a battery ECU 510 from the state
detector 30b in the battery module 100b via the signal line P4, the state
detector 30a, an operation processing device 40a, and a communication
driver 60a in the battery module 100a, and a bus BS.

[0218] The state detector 30a in the battery module 100a and the battery
ECU 510 may be connected to each other via a signal line P3. In this
case, the connector CNc (see FIGS. 3 and 4) of the battery module 100a
and the battery ECU 510 are connected to each other via the signal line
P3. According to this configuration, the detection signal DT2 is fed to
the battery ECU 510 from the state detector 30b in the battery module
100b via the signal line P4, the state detector 30a in the battery module
100a, and the signal line P3.

[0219] More specifically, the detection signal DT1 generated by the state
detector 30a is transmitted to the operation processing device 40a via a
connection line Q1 serving as a second communication path while being
transmitted to the operation processing device 40b via a signal line P1
serving as a first communication path. The detection signal DT2 generated
by the state detector 30b is transmitted to the operation processing
device 40b via a connection line Q2 serving as a fifth communication path
while being transmitted to the operation processing device 40a via a
signal line P2 serving as a fourth communication path and transmitted to
the state detector 30a via the signal line P4 serving as a sixth
communication path.

[0220] In the fourth modified example, the detection signal DT1 generated
by the state detector 30a in the battery module 100a may be fed to the
operation processing device 40b in the battery module 100b via the
operation processing device 40a. The detection signal DT2 generated by
the state detector 30b in the battery module 100b may be fed to the state
detector 30a and the operation processing device 40a in the battery
module 100a via the operation processing device 40b.

[9] Correspondences between Elements in the Claims and Parts in
Embodiments

[0221] In the following paragraphs, non-limiting examples of
correspondences between various elements recited in the claims below and
those described above with respect to various preferred embodiments of
the present invention are explained.

[0222] In the embodiments, described above, the battery module 100a is an
example of a first battery module, the battery module 100b is an example
of a second battery module, the battery module 100c is an example of a
1st third battery module, and the battery module 100d is an example of a
2nd third battery module. The battery cell 10 is an example of a battery
cell, the battery cell group BLa is an example of a first battery cell
group, a battery cell group BLb is an example of a second battery cell
group, and the battery cell groups BLc and BLd are examples of a third
battery cell group. The detection signal DT1 is an example of a first
detection signal, the detection signal DT2 is an example of a second
detection signal, and the detection signals DT3 and DT4 are examples of a
third detection signal. The state detector 30a is an example of a first
state detector, the state detector 30b is an example of a second state
detector, and the state detectors 30c and 30d are examples of a third
state detector. The operation processing device 40a is an example of a
first communication circuit, the operation processing device 40b is an
example of a second communication circuit, the operation processing
devices 40c and 40d are examples of a third communication circuit, and
the battery system 500 is an example of a battery system.

[0223] The motor 602 is an example of a motor, the driving wheel 603 is an
example of a driving wheel, the electric automobile 600 is an example of
an electric vehicle, the vehicle body 610, the hull of the ship, the
airframe of the airplane, the cage of the elevator, or the body of the
walking robot is an example of a main body. The motor 602, the driving
wheel 603, the screw, the propeller, the hoist motor for the hoist rope,
or the foot of the walking robot is an example of a power source, and the
electric automobile 600, the ship, the airplane, the elevator, or the
waling robot is an example of a movable body. The controller 712 is an
example of a system controller. The electric power storage device 710 is
an example of an electric power storage device, the power supply device
700 is an example of a power supply device, and the electric power
conversion device 720 is an example of an electric power conversion
device.

[0224] In the first embodiment (see FIG. 1), the signal line P1 is an
example of a first communication path. The connection line Q1 is another
example of the first communication path (an example of the second
communication path). The signal line P2 is an example of a fourth
communication path. The connection line Q2 is another example of the
fourth communication path (an example of a fifth communication path).

[0225] In the second embodiment (see FIG. 6), the signal line P1 is an
example of a first communication path. The connection line Q1 is another
example of the first communication path (an example of a second
communication path). The connection line Q2 is an example of a fourth
communication path (an example of a fifth communication path). The signal
line P2 is an example of a seventh communication path.

[0226] In the third embodiment (see FIG. 7), the signal line P1 is an
example of a first communication path (an example of a third
communication path). The connection line Q1 is another example of the
first communication path (an example of a second communication path). The
connection line Q2 is an example of a fourth communication path (an
example of a fifth communication path). The signal line P2 is an example
of a seventh communication path.

[0227] In the fourth embodiment (see FIG. 8), the signal line P1 is an
example of a first communication path. The signal line P3 is another
example of the first communication path (an example of a third
communication path). The connection line Q1 is still another example of a
first communication path (an example of a second communication path). The
connection line Q2 is an example of a fourth communication path (an
example of a fifth communication path). The signal line P2 is an example
of a seventh communication path.

[0228] In the first modified example (see FIG. 12), the connection line Q1
and the signal line P1 are examples of a first communication path. The
connection line Q1 is another example of the first communication path (an
example of a second communication path). The connection line Q2 and the
signal line P2 are examples of a fourth communication path. The
connection line Q2 is another example of the fourth communication path
(an example of a fifth communication path).

[0229] In the second modified example (see FIGS. 13 and 14), the signal
line P1 is an example of a first communication path. The connection line
Q1 is another example of the first communication path (an example of a
second communication path). The signal line P2 is an example of an eighth
communication path. The connection line Q2 is another example of a fourth
communication path (an example of a fifth communication path). The signal
line P5 is an example of a 1st ninth communication path.

[0230] In the third modified example (see FIGS. 15 and 16), the signal
line P1 is an example of a first communication path. The connection line
Q1 is another example of the first communication path (an example of a
second communication path). The signal line P2 is an example of an eighth
communication path. The connection line Q2 is another example of a fourth
communication path (an example of a fifth communication path). The signal
line P51 is an example of a 1st ninth communication path. The signal line
P52 is an example of a 2nd ninth communication path.

[0231] In the fourth modified example (see FIG. 17), the signal line P1 is
an example of a first communication path. The connection line Q1 is
another example of the first communication path (an example of a second
communication path). The signal line P2 is an example of a fourth
communication path. The signal line P4 is another example of the fourth
communication path (an example of a sixth communication path). The
connection line Q2 is still another example of the fourth communication
path (an example of a fifth communication path).

[0232] As each of various elements recited in the claims, various other
elements having configurations or functions described in the claims can
be also used.